You’re not being realistic about your ex-boyfriend being a current boyfriend. He’s made it clear that a relationship between the two of you will not work, and you live too far away from each other to make it work. So forget about him. The feelings you have for him are just feelings, and feelings are not enough to make a real relationship work. Compatibility is going to be the currency in any relationship, and you don’t have that with your ex-boyfriend for the 2 reasons above (he isn’t into a reunion and you live too far away).
However, your fantasies about what could have been with your ex-boyfriend may be your round about way of trying to get yourself out of the current relationship you are in, which at the 2 year mark, really should be moving towards marriage — and if that’s not what you want from this boyfriend, your brain may be trying to get you out of the relationship without being straightforward or brutally honest with yourself — or him.
To be fair to yourself and your current boyfriend, decide if you want in or out of this relationship. It’s not fair to yourself or him to waste time in a relationship that isn’t going anywhere.