Why would a man stay in a loveless marriage if he's in love with another woman?

Hmmm. Is he really in a "loveless" marriage or is he just telling you he is? There is the possibility that he is just too much of a coward to leave, and even if that were the case, would you want to be with someone who appears to be incapable of being true to himself as well as those he claims to love? don't you deserve better than that? I would be concerned that he isn't being straightforward with himself, you and his wife. When people truly love someone (and themselves) they are honest no matter what the cost.