Fed up!!

My 6 month old hardly sleeps I’m up every hour feeding her or when she gets up she stays awake for like 3 hours, my partner has come up with this brilliant idea of him going to bed around 10-11 like usually and sleeping until 6am so he gets a full 8 hours sleep while I stay up all night with her just so I can have a 2-3 hour nap in the morning. What a genius so I’ll look after 2 older children all day and a 6 month old baby stay up all night just to have 2 hours sleep when he can actually be bothered to get up with her. Any tips on how to deal with a selfish partner that just will not help at night because I am struggling to cope on maybe 3 hours sleep in a 24 hour period. We argue daily now because of this and it is mentally and physically draining for me now. Any tips on how to get her to sleep through a bit better aswell would be greatly appreciated!