Does anyone else's SO still party and not taking responsibility of their newborn?

I've just had my first baby almost 4 weeks ago now and I thought the birth of our first baby would make my partner pull his head in and stop living the party life every week and weekend but it hasn't. He hardly helps me with him at all, never changes nappys, never feeds him bottles, hardly even cuddles him, and every weekend since coming home from hospital he's gone out to hang with mates, not just for a couple of hours, he's been out the whole night, one Saturday night he didn't come home until 2pm Sunday. He's going out again tonight to a friends birthday and I asked whether I could go instead of him and he cracked it at me. Does anyone else's partner act like this? I'm getting so over it. I feel like a single mother doing everything on my own.