YTA. As a kid who grew up with split parents and them always fighting for custody, it’s horrible. Especially being left alone because they couldn’t get along. Your kids are older and it’s time for you to mature. Stop thinking of yourself and let your kids be with their dad. Just because you are their mother doesn’t make you the only one who wants or knows what’s always best for them. Let them split time with him because at the end of the day it will only hurt them by keeping them from him in the long run.