I hope it gets better for you. It did in a way for me, I guess, my ex Husband and I separated, he saw the children once 3 months later, the next I heard was from his solicitor saying he wanted no further contact with them! That was nearly 4 years ago. At the time I never made it impossible for him to see them, he could have had access whenever he wanted and I told him that. They still have regular contact with his family
My children have both stated they never want to see him again and that is entirely up to them.
As for the new partner issue, I can't comment on the ex as I have no idea what he thinks although he knows about my partner through his family. His family had no issue with my partner whatsoever, he makes the children happy so they are happy.
I hope it will all work out for the best for you. Just try to remember, however you feel about him he is your Daughter's Father and sometimes you may just have to bite your tongue for her sake. Good luck x