Not sure if this belongs here but I thought I would share with you what happened to someone I know (not sure why I didn't do it earlier).
They had known each other for years, really settled relationship until child arrives (who was planned) and H went a bit crazy when fatherhood arrived - couldn't cope. Sent him acting all weird and W kept asking what was wrong, he pulled away, distant etc , as suspected, PA was found out - all signs were there - disappearing, secretive etc. His background was an only child, pressure to be perfect - he also has a very challenging career dealing with some very difficult situations.
So, he moves out. W goes dark and H about 9 months later is complaining that 'he is stuck in the wilderness unable to see where he is going', rocking, very scary. W did not think he was capable of holding down his job based on what she witnessed. Then, he wants back into the marriage after BUT did this with OW still waiting in wings - (so an early return?). W asks him to go to counselling and asks him how sure he was that the reconciliation would work - he said he couldn't make promises. The mistake she feels she made is that she never went to counselling with him. Later, 2 attempts to drive his vehicle off the road, bit of a meltdown - divorce is started. However, even when divorce is final, says he wants his family back and how he regrets everything. It ends with a 'no' in this story but that was because of W's decision.
Anyway, they keep in contact because of child. But the same script was there, blame, projection, heavy drinking (anything goes), secretive, clothes, hiding/spending money at the beginning.
Now he is a very changed man. She says she does not recognise some aspects of his personality and he kept up with alot of his hobbies that he started during his 'crisis', which she describes as being very alien to the person she knew and was married to.
He is with someone else now, but the circumstances described, from what I have been told, it isn't a fulfilling relationship.