Yes it does get better, you just have to change your mindset!
You cannot make your ex do any more than he is prepared to do, nor can you expect him to help you out if he doesn''t want to.
It is no good banging your head against a brick wall or hoping that he will change. You need to find your own support network for those times that the kids are with you and have your own life ( and make the most of it) every other weekend.
Trying to force the issue with him will have a knock on effect on the kids.
Do your very best for you and your kids.
I found that the more demanding I was the more they fought against me.
The best you can do is say a firm no if you believe that whatever they say or do is not in the best interests of you and your kids. Once you do this a couple of times you will gain confidence.
Say yes and then igonre him and do exactly what you want to do.
This is how I handle my ex when he gets too much, even if we are very good friends.
It gets easier when you start breaking *the bond* yourself. I have noticed that even after we broke up we both still and for a long time had the same attitudes and expectations towards each other as to when we were still married. Even after new partners came into the picture.
It takes a loooong time to change these attitudes and there will be some friction, too at times (I once ended up getting hysterical over the phone and told him exactly as things should be... well... let''s just say I ended up saying sorry the very next day and all this in tears) but thin gs will get better.
What helped me and still is, was the realisation that I am now alone with my son whenever I have him and the only person I can rely on is myself and my partner, if he is available, too.