<human>: I feel like I'm overthinking this (I'm very prone to doing this), and it's silly because this anxiety is over a Facebook message, but here I am.

I hopped on my laptop and saw that my BF Alex* was still logged in and had his Facebook messages up. Here's where I went wrong because I'm an idiot who snooped. I get that. 

He was messaging some girl he went to college with and in one of their recent exchanges, less than a week ago, and he basically said (paraphrasing): Just wanted to say that I like you. I'm in a strange situation right now, but in an ideal world, I'd be all about you. It's sad that this isn't an ideal world. We just get along so well.

She responds that she totally understands and is going through some stuff herself, but that they're still friends and that they should hang out more often. 

Alex has never done or said anything to make me worry, but I still feel kind of blindsided because I thought we were doing so well. It's all hypothetical so far and doesn't say anything about getting together or anything overtly cheaty like that, but to openly say that he wants to be with someone else makes me a bit upset. I don't know what background to include because I don't know what would be relevant and walls of texts are no fun. Sorry that this is kind of jumbly, I JUST read it and am at a loss. I don't know if this is something to be concerned about or if I've just worked myself into a frenzy over nothing. I'm hoping for the latter.

Any and all insights would be super helpful!

Can you condense the text into three sentences or less?
<bot>: BF messages college friend that he wishes he could be with her. Am I making a mountain out of a molehill?