Is this a sign we should break up?

22F in a relationship with 22M for 1.5-ish years. We have a great relationship, and while its definitely had its ups and downs, I think we navigate the lows pretty well. In recent months we've dealt with a few trust issues coming from my end, and one lie that, while I'm going to assume he meant for it to be harmless, was actually a pretty big lie/normally a deal breaker if I didn't know him well enough and love him to extent that I do.

My boyfriend is wonderful, but mildly socially inept. He's very outgoing but does not read social cues very well. Its not a big deal, but it means a lot of people misunderstand him as "weird" or potentially "creepy", but in reality he's just eager to make friends and very friendly (read: that guy who makes long conversation when you're clearly in a rush). This causes many girls to think he's flirting with them, and in the beginning of the relationship also made me mildly jealous.

The problem is, when I'm feeling a little insecure (i.e. it takes him hours to text me back, or I know he's with a very attractive girl, etc) I start to act out what I would say in the case of a break up. So, for example, I'll create a scenario where he's cheated on me and I imagine what I would say, what he would say, how we would both compose ourselves, etc. I know this is weird. I also know this is a defense mechanism, in the off chance he does cheat, I've already played out how I would react. It's an attempt to prepare myself (which logically I know cannot be done).

Is this a sign we should break up? Does anyone else do this? Am I just entirely insane?!