[Always *]

Ok for one, I just want to emphasize that I am really sorry that you're having to grapple with this: it definitely sounds like an extremely awkward, unpleasant memory. It's bad enough you know how it happened, you actually had to witness it. And that's got to be hard to live with.

It's just... one thing...

It feels like my property has been intruded upon.

Comments like that are extremely iffy for me. I know you probably didn't mean it as literally as I read it. But if any way you think she's yours and only yours (like property) could just make the situation worse for you. Especially cause, really, it's totally not the era for women being property. I'm not trying to criticize you... It's just, it's really hard for me to let comments like that go.

I think that you need to tell her that, yes, she recognizes how "stupid" it was, but that it's just something that's a horrible memory for you. It's bad enough to know what happened without having visual and auditory memories. But, at the same time, it's probably hard for her to (especially if she's guilty and trying to divert blame: she made a stupid decision and probably wants to forget it). Telling you to get over it isn't fair at all.

If this memory is intruding with your ability to maintain a healthy relationship (ex. if it is affecting your sex life or emotional connection to her) you should get some counselling, I can only do so much through the internet. So that would be step #1. Also, if it's interfering with your relationship then you need to consider if you can ever get over it and if it'll interfere in more serious ways now or later.

The next thing I'd do is seriously consider uninviting this guy. If he isn't close to either of you, given you're history with him it is not unreasonable to say he isn't welcome at the wedding. It's your wedding and you shouldn't have to feel awkward and uncomfortable there. This is especially true if his invitation (or potential invitation) is what is triggering the anxiety/disgust/discomfort (insert relevant emotion) over the memories. There are ways to do this courteously (you can probably google it!). If he has connections to other family members and you don't want him to spread the reason around then googling how to word it courteously is ultra important: there are lots of people who don't want X family members at their weddings, the information is very wide spread. It's ok. You aren't obligated to have anyone at your wedding if you do not want them there. If your girlfriend/fiancee protests tell her that because of what happened that you really are not ok with him being there, end of story: people should only go to a wedding if both parties want that person there, it's a special day for both of you, not just the only bride (or only groom). If one person really doesn't want a person there then that person shouldn't be there. I mean, there are a few exceptions: the mom, the dad, brothers/sisters or the best friend. But thats about it, and this guy doesn't seem to be close to either of you and if his invitation is causing you distress you're entitled to not invite him.----If you were previously able to handle that this happened (awkward and horrible as it was) and it just started overwhelming you after you realized he'd be at your wedding, I'd say shoot straight for this. Make sure you're girlfriend knows how distressed you are!