Is it normal to think we were taken advantage of?

My girlfriend and I had a very unfortunate episode, and I need advice. She lives in an island community, and we've been together for three months. Up until recently she was a virgin, while I've had sex before.

When visiting her home, we were invited by a couple in their 40's for dinner. Since it was some distance to their house, we were offered to sleep over. They proved to be a hippie like couple, living in a big house with a garden. The dinner was pleasant enough, we were wined and dined, while they were asking us a lot of questions about our background and future plans.

We were given a tour around their property, and the evening we sat in their couch and got drinks. At this point, we'd both gotten quite drunk, but not wasted. Then they started asking sexual questions, and soon found out that my gf was a virgin, and that she'd just started on the pill in preparation to have sex. They started talking about how the first time can be painful for the girl, and the wife suggested that her husband have sex with my girlfriend to make our first time easier.

At first I thought it was a joke, and thought nothing of it. But after a while they asked if we had thought about their offer. I told them that they should ask her, which they did. They put a lot of pressure on her, telling her how it would be fun, how it would be easier this way, that she shouldn't be a prude at 18, and finally she agreed. In preparation they start making one of the couches ready, and she went away to pee. At this point I was in a state of shock, and couldn't bring myself to do anything.

So my girlfriend got back, and the wife sits down at the end of the couch with me to soothe me. He puts his penis in her mouth, undresses her, and goes down on her. When he starts going on top of her, I ask if they aren't going to use a condom at least. He tells me straight out that he wants to enjoy the feeling as much as possible.

The intercourse wasn't brutal or anything. She comes with a single "ow" when he gets in, and the wife holds me as he moves inside her. He stops several times to ask how she's doing. After a while he stops to cum inside her.

There's only a little blood. The wife gives us drinks to "celebrate." My girlfriend gets a mirror so she can see the changes down there. The guy claims that the hymen isn't completely destroyed, and wants another go. When he's ready, he starts having sex with her again. This time it's harder, and it takes over an hour before he is done again. It's over, and my girlfriend gets her clothes on.

The rest of the night was really awkward. I try to pretend as if nothing's happened, while the guy keeps telling me how he helped me out and all that. The wife is giggly and makes comments, while my girlfriend tries to keep her dignity by being aloof.

When we finally go to bed, we have sex together. After what's being going on, it's a bit fishy down there, and I'm basically moving around in another guy's sloppy seconds. The following morning we are given breakfast, and are thanked for the visit before being taken back. They agree we all should be discrete about the whole thing.

Now, my girlfriend says she didn't exactly want this to happen, but she was kind of forced into it in the heat of the moment. Neither of us had the authority or the will to just say no. The results were a humiliating experience for both of us. Her having her private parts violated, and I having to see another guy do that to her.

It’s obvious this was some kind of sex game for them, and unfortunately we got caught in it. But how should we deal with it? Should we consider this abuse, although we won't exactly file rape charges or anything, or should we just see this as something that just happened?