I used to work with my wife, but we ended up divorcing after 5 years. I don’t think the fact that we worked together had anything to do with it, but it did make it awkward after the split. I had no problem with the break (and she was the one who left the relationship), but my ex was not happy having to work in the same place as me after the split. But I digress…
I think it comes down to personalities. I have always been able to keep work at work and home life at home, turning one or the other on and off as needed. I would guess that my ex could not do that so easily. I suppose it is just a matter of boundaries.
Perhaps you two need to set up some kind of code to notify the other that it is time to switch modes, without having to criticize the other with a “you’re doing it again” (if that is a problem).
The other side of it is that many couples have the same problem without working at the same place. Some people just don’t know how to let go of work, or don’t want to let go of work. I have been in situations where I used work to avoid dealing with my current relationship. Not intentionally, but you fall back into modes that help you cope best.
So, I guess I am suggesting that you talk about the problem and make time for just the two of you to act like a couple (a coupla what, I’ll never know…). It may not be related completely to the fact that you work together. Making sure that a relationship is connecting is a full time job and takes effort. I think my relationship is an example of perhaps not having both put enough effort into it, but who knows. Remember, communication. It cures a lot of what ails ya.
If I took the wrong spin on what your issue is, I apologize. Otherwise I hope this helps. Good luck.