You're on a rebound cycle even though you haven't rebounded just yet.
You're looking for something better, without sorting out your current situation and making a decision. This isn't fair on yourself or your present partner.
It's serious decision making time. It sounds like your present guy is the one to lose out but you need to finalise it. If he doesn't want to or continues to use ‘guilt tactics', I'd say your decision will be an easy one. Sort it and only then will you have the headspace to think on your feelings for the other guy and your future.