He's as good a dad as he can manage. That's how I look at this type of issue. Him being a good or bad dad is his responsibility not yours. My ex was rubbish and now he's much better so it could improve.
As much as you're stuck with him in life's goings on you can be free of him in your mind. Once that happens you may view him differently, you may not, but you can let him go from your mind even though you are in life's happenings technically stuck with him. I don't see I'm stuck with my ex at all, my children are unless they ever choose otherwise but I'm not. He's their dad not mine. Also my dad deals with my ex, I have nothing to do with him anymore which makes it easier so if you could find someone to deal with your ex that could help you feel better.
Much luck, love and blessings.