Quoting Undertheweather:" That's what I was thinking I'd have to do. I'm just worried if he knows how much he's interfering he ... [snip!] ... been interested in me for a long time. I worry that telling him will make it worse. But maybe it's a chance I have to take."
Well if you completely cut him out of your life, there is nothing he can do. It means you dont see him, dont talk to him, and have absolutely no contact with him. Also if he would try to make things worse, then is being disrespectfull to you, and to your marriage, which is an even bigger reason to cut him out.