Tbf, dad or not, long term partner whatever I would never let someone else sleep in my sex stained sheets. I just think it's really unhygienic regardless of the length of time you've been together. Just change the sheets it's really not that hard. If it was unexpected like H was ill and came through in the night then yeah I suppose but not in any other situation.Irrelevant whether its their dad or not… they still slept in a bed that i’d had sex in.
And with the greatest of respect, yes she lives in a hellhole but you dont know she hasnt changed the sheets. Youre assuming.