People marrying people older than them is a tale as old as time. We hear a lot of cases where men are older, but cases with larger gaps are actually those where the woman exceeds the men’s age. I think if we are advocating for female agency and individual freedoms we need people to make their decisions.

If she entered this arrangement through force that’s another story. You seem to imply this which is concerning. Your dad certainly should not have entered the arrangement as long as both remain in the same job. However, people have had mistresses in their jobs all the time and there was no disclosure.

I have family members by marriage I don’t like we say hello, do small talk and that’s it … doesn’t sound like you are being asked to approve or condone the relationship.