I feel really bad, I kissed my work husband.
Oh my, why would you kiss your work husband?
We're so close and we work working so many late nights, it just happened and I couldn't stop it.
Couples are expected to be loyal to one another, no matter how much time they spent apart. Its wrong to kiss someone else who isn't your spouse just because you spend a lot of time with them. It's also can cause issues at work to have an affair with a co-worker.
It's going to be very awkward between us and I'm not sure what to do. I don't want to tell my husband.
Tell your co-worker the kiss was a one time thing and it was a mistake. Tell him you want your relationship to be professional only. You need to tell your husband you made a mistake and the two of you should work through this together.