How do I stop resenting my friend's relationship?

Basically she started messing with a guy that had already been in a relationship for 3 yrs. No matter how many times we told her to honor his relationship and leave him alone, she would go down to his dorm and drink and they’d fooled around anyway; he ended up cheating w/ her.

His gf dumped him for it, and now he and my friend have been together for almost a year. I can’t stand that, in part b/c around the same time I also had a guy I really liked too but he was already in a relationship as well, so I chose to respect that and leave him alone (which of course I don’t regret)...yet my friend acted the way she did, and is now in a relationship that I feel like for the past year now she’s been rubbing in my face.

For example she’ll straight up just start making out with him in front of me, and then look over at me as if to see if I was looking (but I’ve started ignoring them/ looking down at my phone when they do that). She goes on and on about their sex life, her pregnancy scares, the couples challenges they do, and how she’s “permanently” taken now (she’d never had a relationship before him).

And last semester, she asked me to help her with a photo project, which I had no idea would pretty much turn out to be a couples photo shoot, with me standing there having to take over 60 pictures of them making out and holding each other. Even he addressed that, but she claimed that wasn’t her intention.

I just hold my tongue through it all because I don’t want to come off as the “single, bitter, jealous friend”; “what’s done is done”, “it takes two” and all that stuff; but I seriously resent the situation because it makes me wonder why people can do messed up stuff and basically be rewarded for it.