The intent to cheat is just as bad as actually cheating?

Me and my boyfriend recently had a fight where he basically told me I’m passionless and he cares more than me, even though I’ve constantly been there trying to be supportive of him. Since the fight I can’t help but think about the fact that he gave his number to another girl a few months ago and was flirting and talking about making plans to meet up with her. Since I found out he has stopped talking to her but I’m so worried now that he’s actually going to end up cheating with someone else. Am I dumb for even staying with him after he did that