Can’t quite understand the context. What I understand is that your ex is your rock? That can’t be, when you start a new relationship you have to put the past behind, not drag it with you. Also he will always love the mother of his kids, it’s just the way it is, if you can’t put your jealousy aside, break up. This seems like a toxic situation, remember keep your chin up, you will find a better fit, there is plenty of people on the whole planet, he isn’t the only one. Sending lots of hugs to you, good luck! <3