What reasons do men use to justify staying with a repeat cheater?

So my stepson has a daughter from a previous GF. I had tried to warn him he was headed down this road and may not be a train he wants to ride but we live-n-die by our decisions and he made his.

GF eventually cheats on him or finally gets caught Either way. When the daughter was a baby, she ends up in the hospital because she started convulsing and almost died. Turns out she inherited her dad's medical condition. Also puts an end to any doubts about her being his daughter.

We drive down to the hospital. Ex GF and her BF are there but we knew they would be. For the record, I've been cheated on in both my previous marriages so it's a sore issue for me and this was the guy she cheated with. Both the wife and I wanted to hate this guy. We really really did. The first time we met him was at the hospital and I have to give this guy credit. He's got one big set of titanium balls on him. He's no one I was worried about physically but he's a brave SOB. Wife and I are sitting there when he comes over to introduce himself. Why, IDK. It is VERY clear that we don't want to talk to him. However, he was super polite, yes/no ma'am/sir. etc. He tells us about how he's helping care for the baby when she's at her mom's and so on. I can't recall the whole conversation of that day but the point being is by the end, wife and I are driving home when I tell her that, despite how much I wanted too, I can't hate that guy. Wife replies she's thinking the same thing. We wanted to hate him SOOOO bad but he was so damn polite, attentive to the doctors talking, etc. He truly did seem to have the baby's best interests at heart.

Now this is the weird part. He and stepson actually became good friends. In fact, for a time, all four of them (stepson, daughter, ex GF and her BF that she had cheated with) all lived together for a time. No, it wasn't a polyamorous (sp?) thing as stepson was dating girls but they're not rolling on cash so they lived together as a means of convenience and cut costs for them and the baby. And honestly, we feel the BF is probably the best thing to happen to that mom as he really was helping take care of that baby. Mom isn't the most responsible person. It's really a convoluted story and one I know I would call bullshit if someone was telling it to me.

Since then, we've learned he was abuse pretty bad physically and sexually growing up. Some fucked up stuff as his mom was far from providing any sense of a stable home life and had rotating, abusive BF's. He craves having a family of his own and they've since had their own kids. The guy is actually smart as shit too. I feel he'd do well in a college STEM program. Unfortunately, that's just not how things worked out for him. Not long after I met him, I tried to talk him into breaking up w/ her saying that she's cheated on stepson, she'll cheat on him too. He replied he understood that but was willing to risk it. And she did. We even found out she cheated on him w/ stepson. While technically none of out business, we jumped on him for that. Pretty fucking douchy. That was yrs ago and he's had a couple GF's since.

I feel bad for the guy but they're still together. He still loves her. I guess that means everything to him and thus is willing to put up w/ her antic's because of it. He shouldn't have too though. I feel he really deserves a lot better. He truly is a nice guy. I don't me the "nice guy" trope of a guy who complains he can't get a GF but rather if I had a daughter, I would have absolutely no objections of him marrying her because I know he would treat her right.

/r/AskMen Thread