if you really love your wife and want to stay married to her then i'd fight for her. step up and start pursuing her and wooing her. if she can fall out of love with you then she can fall back into love with you. if she is responsive after doing that for a bit then tell her she needs to break it off with the other guy. don't stop pursuing her once you get her back though. you have to work at the relationship and keep the love alive and not coast along. why not give it all you've got before giving up on the marriage? if you don't, i think you'll regret it. getting couples counseling would be a good idea too.