Thinking about this girl on Christmas, and had to take this out?

I caught feelings for a girl early this year who was in an abusive relationship. We all worked together. The guy was very insecure and madly obcessed with her, he'd always give her sht if she looked at some other guy. Constantly upproached and tried to put me down when I was working beside her (didn't even realize why he was doing it until a co-worker told me it was because she was near me) Has hit her before in front of everybody, and for 5 months of the 6 months i never saw her with a smile on her face and constantly saw him giving her sht. Literally no love shown. Looked like he was always pissed off at her. God knows what was like at home.. She was very vulnerable to the point of blushing if some guy was nice to her. Then all of a sudden, in that last month, I see her happy with him everyday..

I know the guy.. and he struggles alot mentally, He does not deserve her but he isn't a bad guy.. You can attack me for saying that tbh. But thats what she saw in him I suppose. She stuck with him. Supports him and would give up her job for him. He has the sweetest girl I've ever met by his side and I envy him every second. And I haven't seen neither of them for 3 months and possibly never will, I still think about her. She deserves so much better, and I know she will eventually realize that, but... I won't be there, and even if I was, it wouldn't be me. It's Christmas and I'm typing this dumb sht.