This is a complex one. 

But, the fundamentals are that my partner, that I love so, so much, occasionally gets overwhelming guilt. His children are 6 and 9. The 9 year old misses her mum when spending longer stretches of time with dad (my partner). She cries, and is sometimes inconsolable, despite my partner being the most wonderful dad. 

He initiated the split with the children’s mum. She did not want to split, but he was incredibly unhappy.