People say cheaters can change

There's the whole ONCE a cheater always a cheater.... and then others say there so cheated and changed and there happily married etc. But if your man cheats on you with your first cousin, mutual friends, and then his own cousin resulting in 3 children, can he change.... he got us both pregnant at the same time, we both have daughters to him that are only a day apart in age, we also have 3 children. He has 6 in total, one was only born 3 weeks ago. and he tried cheating on me with her again. But now says he's had a life changing moment and wants to change big time. Can he do it do you think, I need answers 😭