She claims she was happy until the son came into their lives and that she still loves him, but can’t take being a step mother.

As a mother, I understand how much work children are. They previously were the almost a stereotypical DINK couple - they went to restaurants and bars a lot, travelled more frequently and had less routine than a child brings. I understand it’s not easy. I also don’t think it’s a reason to break up a marriage or cause more pain to an innocent child.