Jess, he is no longer the man you fell in love with so the best thing IMO is to get out and focus on being a mummy to that gorgeous little girl. It will be hard but you have Gudism's offer and there are always alternatives, you just have to look around. The more you stress and get upset, the harder being a mum to Lyla will be.

As for your charming sister, karma is a b!tch.

It will take a while for you to feel OK again but it is his loss. He also loses the most precious thing in his life (both you and Lyla), even if he is too stupid to realise it. One day he will, and it will be the biggest regret for his life.