I’m quite surprised by the responses here.
Of course, no one should be calling their ILs Mum and Dad if it makes them uncomfortable, but I’m quite surprised to see this is seen as outdated or cringey.
I usually call my ILs Mum and Dad when I’m in their company, but when referring to them in their absence, would say their names, or ‘my ILs’. If talking to OH about them, I refer to ‘your mum and dad’.
They never asked me to call them Mum and Dad, it sort of evolved naturally. I often call my FIL Pops instead of Dad actually. I sort of think of those words as their names, rather than being how they are related to me. I’m not sure that will make sense to anyone else but it makes some sort of sense in my head!
I don’t have my own parents any more. My ILs are really nice people and I love them but they aren’t, and will never be, my mum and dad. It’s just something I’ve ended up saying, without really thinking too much about it.
The one thing though that really hurt me and which still stings when I think about it is when FIL said to me, after my Mum and Dad had died: ‘We can be your Mum & Dad now’, almost as if I was supposed to feel somehow honoured about that. Obviously, it was an awful and stupid thing to say, but my FIL has form for being a bit of an insensitive dick at times.