Need Advice !

Hello everyone I'm 19 and I'm 39weeks pregnant with my first baby well my baby's dad has a 3 year old daughter to a different women who is married now and has 3 other kids well she hates me and and told my son's father that if he'd help raise our son that she'd keep his daughter from him so now he blocked me on Facebook and blocked my number and wants nothing to do with our son because of his first baby mom starting stuff with him and now he's mad because my boyfriend is stepping up and is being there for me and my son he's super excited and he's even looking for a house for us to live in together and everything but my son's father he's family hates me now because of me letting my boyfriend being apart of my sons life am I wrong for that ?