How to win back someones affection

I know I probably sound like a complete nutcase but I'm pregnant with my 5th baby and my partner has recently decided that he wants to end the relationship. He blames me for things like him not being happy and making choices he wants to in life.

With all the kids it's hard to find time to do adult things or our own things and this has become too much for him and it looks like he would rather leave his family and he sees the extra time alone and free time plus financial benefits of not being part of our family anymore.

Is there anything I can do to save my family? I don't know why he doesn't love me anymore and when I try talking to him all he says it he wants more time to himself. Is it over for good or is their any hope ?