Rough one because after 4 years, the initial infatuation is gone, biochemically. It's a very common time for couples to break up, the 4 year mark (with the next one being the 7-year itch). More on this in my relationship series in my signature.
So, no guarantees here, but if you want you can tell him to talk to me. It's something I specialized in, I've salvaged one-down relationships for many of my clients back when I was coaching. I don't coach for money at all anymore but I'll exchange a couple PMs with him for free if he wants.