Unpopular opinion perhaps (haven't read all the multitude of replies to this post): I am woman willing to say sex is a NEED. I am fairly sexual and don't get enough from my husband. That's fine--what I do get it great (so Great). That said, if I got none--it would be more difficult. Sex is about reproduction (of course) and really about closeness in marriage. From a religious POV is it a recommitting of the marriage promise. I do think your wife should try to look into endocrine/psychological/etc. causes for her lack of sexual desire. It is unfair to you that she isn't willing to be more giving. It is a spouse's duty to attempt to be there (within reason) for each other. Especially if they expect fidelity--not that you should act on your impulses. That is all kinds of asking for trouble. Ditch the Ex. That's a mess best left alone.