Never give anyone you're not dating relationship time and energy. Trying to get with another man's fling is bad idea ethically and it could lead to violence.

You don't want to give this up, so make a deal with him to do something be wants.

You know what you need to do, leave her, no one desseves commitment, it's not losing a girlfriend, it's gaining a better understanding of redflags.

Go to the class, hobbies and skills are way harder to replace than a SO. Never give up self improvement for somone.