I keep having sexual dreams about a ex-coworker.

So this one guy I work with is really handsome, smart, and funny AF. And we talked every once in a while and some of the things he's told me have made me start dreaming about him sexually a lot, they're especially more sensual when I sleep next to my bf. We've texted a few times too, but I deleted so my bf don't see them. I'm seriously thinking of ending things with my bf because of this as he's no longer turning me on or attractive to me no more and hitting this ex-wotker up. Any serious advice would be helpful please.