Is it a dealbreaker to have different views on cheating?

My bf tells me from time to time that he gets why people cheat. We we’re watching divorce court and the guy who has cheated multiple times said he did it because she doesn’t give him head. My bf said “i see where he’s coming from” he says shit like that all the time and he’s cheated so much in the past. Not with me but on his ex’s (he bragged about it) I on the other hand will never ever see why people cheat. when he says stuff like that it makes me think he’ll find some whack ass reason to cheat on me. “Well you don’t give me enough attention!”, “we hadn’t had sex in 3 days so I got it from someone else!” Am I overreacting by being mad when he says he can see why people cheat?