My dad isn't remarried but we refer to his girlfriend (for want of a better term) Granny (insert name here). She is great and I love that DS calls her that
My mum's parents are both remarried and I have always called them Nanna and 'partner's name' and Pa and 'partner's name'. It feels weird for me to call them anything but their name. I guess if they had been remarried before I was born then it would be different.
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