He's funny, smart, responsible, loving.
So far you are describing me.
head over hills
"head over heels"
(that's always been an odd saying since it would be more correct to state, 'heels over head' to express something like 'upside down n love. In 1864 Thomas Carlyle used the phrase correctly in his "History of Frederick the Great")
his ex uses their daughter to get in the way of our relationship.
the ex- was in his apartment,
Those comments look very related. Was the ex there to pick up the kid? Are you (perhaps) a bit jealous of the attention he gives his child?
He's shut me out now, and won't talk to me.
Are you the one who began the argument? Were you more emotional than him?
I have the feeling his ex is threating from keeping the child from him if he continues with our relationship.
She can't legally. ... unless there is something in your past which can hurt him.
should I just wait....
Write him a letter expressing your sincere feelings (no e-mail which is too impersonal).
Attempt to be the woman you want him to think you are (that last one is the most difficult).