Is there such a thing as intellectually cheating? I [25 F] feel like I'm cheating on my boyfriend [25 M]

To start off, I've [25 F] been with my boyfriend [25 M] for almost 3 years. We've been through thick and thin and I love him. I just don't think I can connect with him at an intellectual level. I can't even have good conversations about things I'm interested in or vice versa. The only overlap for conversations that we have is our profession and our dog. (To add, we did get into a relationship after having worked together a lot, though now we aren't working at the same place.)
Now I think I'm beginning to realize that we might not have that much in common and I don't know what to do. I really do love him and we have great moments but when those die down, I don't know what else is there. Nothing to pick your brains at, nothing to talk about other than surface level and shallow things. And I try to talk about his interests, but I really can't get into basketball, cars, or shoes.
I have this coworker [25 M] (who has been a good friend of mine for about 2 years) that I can really connect with. We have great conversations and I really enjoy spending time with him but deep inside I feel guilty for enjoying it. I don't really find him attractive (physically) but the thought pops into my mind, that what if I met him sooner? What if we met in different circumstances? I don't really flirt with him or make any advances, though I still talk with him about a lot of things that on the other hand my boyfriend and I, don't connect on.
It feels like I'm emotionally or in this case intellectually cheating but I don't know. It's only been in my head and I haven't really told anyone about it. I don't know if I'm making any sense but it's really been bothering me. Am I just magnifying the want for an intellectual connection since that's something my relationship is lacking? Am I actually cheating? I don't know what to do.
TL;DR: I don't connect with my boyfriend on an intellectual level but I do with a colleague. So it feels like I'm cheating since I enjoy spending time and talking with my colleague.


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