I'm not going to give you any ethical moral mumbo jumbo. Instead I'll give you advice from personal experiences. Do what you will with it.
If you want to keep him.
You need to stop caring so much about him.
You are the lover.. You are the mistress.. There's a certain aura of forbidden fruit about you. If you spend too much time with him( and frequently) you'll become mundane. Stay busy. See him only once a while. You are a free woman. go out and date and explore. Who knows. You might find someone better.. That's the bright side of being single. Options.
Heck, date those other options while your at it.
Also don't be needy. Don't be texting and calling him for for validation or affection.