Me = single. him= D/w 2kid. ex still in love w/him. he says not in love, but can't say no to her. what to do?

here's the deal...he left the wife 1.5 yrs ago, slept with her last x-mas before we met. We started dated in March. She turned up telling him she was pregnant in May. I broke it off, told him to try to make it work for the sake of the kids. He said it never would. 2 months later we decided to start dating again. However, he still can't say no to her or tell her about me. I understand his kids are going to be a priority and I'm cool with that, but I question his involvement with her. She's always in financial need and he always bails her out to the detriment of his own financial stability. I want him to support his kids, but is it too much to ask that he stops supporting her? There's no reason she can't support herself. i just feel like he's still hung up on her because he's always giving her money. Am I right, or should I be more understanding?