My DF remarried although I still (30+ years later) have no idea when. I have a good relationship with DF and he comes to my house every week or two for a cuppa.
My SM hated the fact that I, as a young teenager, had a claim on my dad. Looking back, I think she was actually jealous. She got on much better with my brothers, and still does.
I have never stayed at their house, even when I was young. I remember dad complaining that we never popped round to see him so, when I was 13, I got my bike out, pedalled round and knocked on the front door.
SM opened it a crack and looked at me with one eye and said, "yes?"
"I've come to see my dad."
"He's not in."
"Oh!" (Genuinely confused) "he told me he would be."
"Well, he's in - but he's asleep."
"Oh."
Then I heard my dad talking in the background. She looked at me and said "I suppose you better come in."
I remember stepping around her, through the crack, because she didn't hold the door open. As my dad saw me - and beamed with delight - she said quietly, "you're not staying long enough for a drink, are you?"
I didn't know what the right answer was so I shook my head.
I don't remember how long I stayed or what happened next, but I never, never went back.