Recurring dream usually means there is an issue in your life that you have not resolved. But to resolve it, you have to first realize what the issue is. I think you have to be honest with yourself when asking yourself a question if you have romantic feelings towards this person, even if it will be unwanted or hurtful.

Lets say you realize you do have feelings for him. Sit down somewhere where you can have peace and quiet and try to solve your problem. Even if you say in your mind that you are both married and you can't start anything with him, that's not enough. You need to hear yourself say that and make a decision about it. That's what I would do, anyway.