Planned pregnancy.. Gone wrong

We planned our baby. And now he's gone home to his moms house and he wants to take a step back in our relationship.  I don't feel like that's what you do once you have a baby involved. I don't understand how or why he is doing this to me. I didn't even want another baby, but he wanted a family with me so i decided to have one more with him.  And now he's gone. Like...... What?