If a guy does something bad to a girl in a long term relationship, like cheats on her, that girl is not going to forget the past and just turn the page.
If she stays with that guy, they are going to have to build up lots of trust, and he is going to have to prove to her that things are changing for the better.
For me, going 5-3 isn't enough trust yet, and especially after that Thursday nighter, those past 17 years of failure start to creep in my mind again. It's good that you are optimistic, I'm just not there quite yet