Long story short, my married friend and I have known each other for 5 years and and have had a rather flirtatious relationship in those years. I have always found him attractive and have found that my lustful desires intensified over the last couple of years but would never do anything due to the fact of his marriage. I'm 95% sure he feels the same way as well due to the way he acts back. Lately he's been really argumentative with me and I feel as though maybe he is resentful of the fact that he has these feelings but doesn't want to act upon them. I still catch his wandering gaze most of the time but he seems more aggressively nasty toward me. Is this normal behaviour when lust is not acted upon?