If he's remarried .. I would say that the clause is a mute point. Make sure you talk to your atty before you do this because modifying a decree is not a walk in the park. My STBX has issues with drinking .. if I said he can't drink while he has the kids .. umm .. he only has the kids 2% of the time .. so who does that affect, me or him? LOL? Well of course it affects me more .. so there were a lot of things I rethought before putting it into writing. NOW if he divorces again then the clause would go back into effect or at least that makes logical sense to me. I don't know the cost of modifying a divorce decree, DO seek counsel before trying to do so.

It depends on the specifics of how your clause is written. Normally they forbid co-habitation if *unmarried*. Unless you are claiming that he is now in violation of the clause by living with his wife, it is still in force.

If you wish to move in with the person you are seeing, you will probably have to get married in order to comply with the clause.