<human>: He's a co-worker, but he's in school now.

He is a great guy. We got into a fast friendship, and within a week of actually speaking to each other he revealed that he has had a crush on me since the first time we had talked on his first day at work. At the time, I did not have feelings for him whatsoever and politely told him this. He took it very well, because he is a nice guy and not a Nice Guy(TM), and we have gone out together many times since then.

As we've grown closer, however, I have developed a crush on him. Perhaps I always had one and I didn't realize it, but anyway it's full fucking blown now.

The catch is: he and I are fundamentally different people. He is a somewhat seriously practicing son of a rabbi while I am an agnostic-atheist goblin who disagrees with most tenants of his faith. I don't care as a friend that he is religious, but in the context of a serious relationship I feel like something like this would be more harmful than not. There are several other key differences, but I don't really want to go on a tangent in the OP. Feel free to ask ITT if you're curious/feel like it's important.

So I understand that is a relationship that likely will not work out romantically, but I feel conflicted about my crush anyway. I feel almost rude for not telling him how I feel, but I think that it would make things more complicated if I did. He has been trying to move on from his crush on me since I initially rejected him, and I feel like admitting my crush would undo all of his progress. At the same time, I have a habit of telling the truth (when it's not necessary) and I don't really want to be a liar.

Can you succinctly summarize the text in 1-3 sentences?
<bot>: I have feelings for someone who has feelings for me, but I know with high certainty we would not work out. Should I tell him how I feel, since he offered the same courtesy to me?