Maybe he wasn't paying attention to the right things, or taking her for granted, or something. Cheating is a reaction too.
Yes, maybe he did take her for granted and that cheating became the reaction, but they could have talked it out. But she resorted to cheating rather than opening up, which ultimately was her choice also. Both of them are at fault and chose the choices that they thought would make them feel satisfied, but unfortunately, I know those choices didn't. Hopefully, now that the damages are done, he can move on—they can move on.
But really, some people have language gifts - I do not! :D
Haha same! I do have the ideas, but I somehow struggled writing them down decently. They mostly end up jumbled if I didn't take time arranging them and omitting the redundant ones, but I'm hopeful that with constant practice, I can improve it.