How can I forgive my parents?

I have a problem. I grew up as an only child in a very liberal and hippie-like family. Both parents have a pretty high education, privelieged jobs, and a very open and casual relationship to drugs and the like, and sex in particular. Through my childhood they would often walk naked around the house, and not be very discreet about having sex in my view. They always tried to instill in me the same values, although I'm more conservatively minded. They've even wanted me to watch as they were doing it. Up until now I've just accepted their antics, and learned to live with it. Then again, I never would have thought about what would take place later on. I'm sorry this comes across as a rant with sexual details. I just need to describe what happened to the fullest, in order to understand it.

Basically I brought my girlfriend home with me. She comes from a troubled and somewhat impoverished home, and naturally she wanted to stay away for some time and instead live with me. My parents seemed to be happy that I finally got a girlfriend. Before this, I had just been with one girl that I never took home. Well, one night they wanted us to drink with them, and started asking us all these personal questions. They soon found out we've never had sex, and that she in fact was a virgin. So they suggested that they could help us and make our first time together easier. Of course I didn't take it serious, I just thought of it as a joke and laughed at it. The topic changed, what her future plans were, her education and background, etc. After a while they had gotten quite drunk, and we ourselves had way too much, to the point where things were staring to get blurry, and I wanted to call it the night. When my girlfriend came back from the bathroom, they poured us more drinks, and asked if we had considered their offer. They claimed that sex would be much better when there was no virginity involved, no pain and no resistance. They argued that this was quite normal in different periods of history, that an older man would help a younger couple in this manner, especially fathers when their sons got married. I was pretty spaced out by it all, and told them it was up to my girlfriend. My father asked my girlfriend if she had seen a penis before, and when she said no, he got up and unzipped his pants in front of her. He pulled it out, dangled it in front of her face for a while, and told her to open her mouth. When she did, they had the answer they needed, and he put it in. That was the start of the most humiliating thing that has ever happened to me. She gave him a scared and very awkward blowjob for a while. We were told to kiss each other, while they prepared one of the couches as a bed, all the while his penis were pointing everywhere. At this point I could not bring myself to stop it, it just seemed unreal to me. I gave her some careful kisses, and couldn't avoid the taste. My mother got behind me to hold me as we sat by the foot end of the bed, and my girlfriend got her pants and panties undressed, but not her blouse, as she was to embarrassed to show her boobs. Basically she had gone more or less limp while this happened to her. My father pulled her legs fully apart, and started having a "make out" session with heir vagina. It was wet, sloppy, he used his tounge alot over the small opening, and at last he spat at it. At this point it became too much for me, and I wanted to moan and protest, but my mother wrapped her arms around me and tried to soothe me. My heart was racing wildly at that point. What followed was something out of a horror movie and a nightmarish medical operation. He got on top of her, and started to try to penetrate her. At first it was light and systematic poking that spread her lips a little and didn't hurt her, then more determined pushes that made her grunt with effort, and then eventually started to hurt. He paused a little, let her complain, and then started over again. After a cycle of light poking, he pushed, and this time he didn't stop even though she was crying. Although her vagina was way too small, it was still made for sex, and he achieved a full penetration. Sitting behind them, I got to see between their legs. He made some motions inside her. After just a few thrusts, it was his turn to moan loudly, and he came inside her. Resting for a while on top of her, he pulled out carefully, and that was it. I had gotten completely sober in the process. That was the start of a frentic clean up process. My girlfriend got a towel to have between her legs as she sat by the table, and my father wiped the blood with her panties. We then could sit with drinks and "celebrate" my girlfriends entry into womanhood. I was feeling dizzy and sick, almost outside of my body. They were pleased with themselves, and I was in a state of shock. They claimed it was more or less a favour for me, because even though they left me a "love gift" that would probably smell a bit fishy in the morning, I now could slide right in with no resistance, and a vagina being a bit kinky was nontheless more exciting. They told my girlfriend and I to cuddle and kiss, and went to get a hand mirror. Using it, they found out the hymen wasn't completely gone, and so my father wanted a new go. My girlfriend had just stopped bleeding, but still he wanted to do that to her again. Only reluctantly did he agree to wait until we had finished our drinks, but he managed to convince her to take of her top. It was all a drunken stupor. My father must have been quite drunk as well, because this time he couldn't quite get it up. He told my girlfriend to roll over and show her butt, and she refused. At the end, my mother gave him a blowjob so he could achieve a full erection. Then, a more complete version of the humiliaton began. My father got between her legs, and my mother and I sat behind them as he started with her again. He started slowly, and then used an endless variation of rythms and strokes. Fast, hard, quick and firm, it went on and on, since he wasn't in any danger of cumming. In fact, the alcohol had made him numb and almost immune to ejaculating. My girlfriend was very sore. At one point he stopped, and asked if we liked the view. My mother said the view was perfect, and whispered to me that he was very vain. He went on humping away between my girlfriends legs for almost two hours, and since it was hard to look away, I practically spent the whole time staring at what was going on. At last he increased the tempo, used all his force, and raised himself to cum in her. It was obvious enough I was getting my second love gift. He collapsed on top of her in a pool of sweat. This time they rested together for quite some time, while the room smelled like sex. At last he pulled out of her and wiped his penis in her pubes. My mother kissed my head, and told me to lay next to my girlfriend. She put a big blanket over us, turned off the lights, and left with a giggle, joining my father in the their sleeping room. Luckily enough, and thaks to the alcohol, we fell asleep pretty quickly. The next morning I had to remember what had taken place, every detail getting clearer and clearer. I wanted to reclaim my girlfriend in a way, and she let me. The comment had proven right, it smelled a little fishy there as I went down on her, and when we were having one of two gentle intercourses in the morning, I was pushing around in my fathers sloppy seconds. It felt cold and sticky. He had done a good job, at least, since there were no remains of the hymen and no resistance. Her pubes were crusty, and I ended up with a black hair on my tounge that certaintly didn't belong. Yuck!

My girlfriend says that what happened was very unfortunate, but that nobody was maimed or killed, and that we went along with it. So we should just live with what happened. We now have an active sex life, but I just don't think I can forgive my parents. For her, they are a couple of strangers, but I have to relate to them for the rest of my life. So how do I deal with being humiliated this way, and having to parttake in this borderline incestous act? My parents of course don't understand that I have problems. In their view, they just did me a favour, although my father of course had his ego satisfied by making me watch while he was doing my girlfriend ... For them, an experienced lady is much better than a virgin, and a dirty vagina is more exciting than a clean one. For me, it's the opposite, and I'm devestated by all this. They thought they spiced up my and their own sex life, and instead, we have these catastrophic results.

to forgive is to forget.