azure is right, you have to reasonable about this and not gloss over his glaring flaws because you still have feelings for him and hope things will work out again. No matter how much you care about him, if he does not feel the same way, you guys cannot and will not ever work out. It's a tough pill to swallow but something that has to be accepted. He is always going to have a piece of you, and it's not consolation that you have to keep in touch with each other concerning the kids. All you can do focus on yourself and what makes you happy, including your kids, and you will find somebody else. Your self worth isn't determined by what he wants and doesn't want. He is passing up all you have to offer and there are consequences with that. Only fair he should have to experience them.
His actions speak volumes about how he feels. He doesn't respect you and is pathetically trying to get with your cousin. Brazen enough to ask you to help him. He's no good for you. Accept this fact and tell yourself this. We are all fully capable of learning and growing, but his actions are showing his true colors and his focus is on getting with other people instead of changing himself for the better. If you were to get back together and he hasn't worked on himself or changed (and either have you), logically you both would be destined for break up again. The honeymoon is over, he's a jerk and is looking out for only himself right now. You should be looking out for you and putting yourself first as well.
Waking up next to a beautiful girl,
Step outside and say hello to my beautiful world.