I'll be 60 in July. I've had my share of ups and downs with relationships. You and your wife must be best friends above all else. If you're arguing now and there are serious trust issues, you ain't seen nothing yet if you get married. You know what you need to do. If you don't move on you're going to be miserable for a long time. There will be some short term heart break, but if you stay in a relationship thats going now where for a long time, you're only hurting yourself. Good luck, just my two cents.