Much as I dislike Sarah, I hope she's left Jim. He always seemed so obsessed to show he'd moved on from Tanya by marrying and having kids super quickly. Also the fact he chose to do with Sarah whose (in the loosest possible terms) a model to rub it in to Tanya that he can date a slim successful (in his eyes) woman who won't question him. Where as he probably thinks its karma for Tanya dumping him, as her acting career never really took off and she always tried so hard to show much weight how she'd lost but not naturally slim like Sarah. He's just used Sarah as a baby machine to have one up on Tanya with a 'look at me, I did it first, I beat you!' kind of attitude.
Sarah deserves someone who genuinely loves her and doesn't use the children as cash cows. As I think that was all Jim's idea from the very beginning and anything to boost his ego on how he's trying to prove he's the world's best dad. When Sarah doesn't get any thanks for actually being pregnant, giving birth and looking after those children 90% of the time. Whilst he does what all day? Draw some doodles, film his daughter for some engagement when she clearly is not happy about it and post videos of him getting dressed. He wants to put off getting a real job for as long as possible. The freebies aren't going to last forever Jim!