I'm so depressed..

Why is it so easy for the father to give up? I'm 3 months pregnant and keep our soon to be 1 year old on my own, he just gives up, rubbing it in my face that he bought a new big house and a new vehicle for himself and he has everything, TV and internet and a phone and a good job, while me and my son are just always on the move, moving house to house for the past year since he was born we been moving, stayed with his dad for awhile at his grandmother's but it got to difficult to be what he wants me to be, so I left.. and now he's just rubbing his success in my face, but won't help at all with our child and pregnancy.. why is it so easy for him to give up on the children.. and just mock my struggles ? :(