@affor
I was where you are in the past, and all I can tell you is you can either continue to feel this pain perpetually, over and over again, or you can cut the cord now and start the clock ticking to where the pain ends. In the end I made a drastic change and left the country. It's about 10 years later now and I'm happy and married with kids. Now I have kids, I know I'd never leave them, and it appalls me even more what he and I did when I was single and he was married.
Please cut the cord now and start healing. You deserve so much better. He's got a nice cosy family and all that goes with it, and you've got nothing. Nothing.
If it's gonna take 6 months to get over for example, start now and feel better by June. The alternative is, you don't start now but instead delay to what, this time next year? You end it then and it takes 6 months to get over so that's 18 more months of pain versus 6 if you do it now.
Don't want to clock just in case? Just in case what? In case he rings you to mess with your head and end with "yeah I still can't leave her". Or " maybe I'll leave her" to keep you hanging on, changing to " yeah I still can't leave her" a few weeks later. It doesn't matter if he calls or not, the outcome is the same. Pain, pain, pain, temporary high, more pain.
Just cut him loose and don't feel sad, feel happy. Feel free. And you know what? If he ever was gonna leave (which he isn't), you binning him off is the only thing that would compel him to . Because you become instantly more attractive the minute you're not at his beck and call. This isn't going to happen but if it can serve as motivation, so be it.
Good luck.