My mother left our family - with my dad's best friend - when I was 12.
Even before that I was pretty sure she didn't like me as I "preferred" my dad (who was great).
I tried after my dc were born, but it was all on her terms. When they were "too old" my mum gave up. She loved babies/toddlers but beyond that wasn't interested.
She blanked them at my brothers wedding last October. I knew (from bitter experience) that she'd blank me, but her attitude to my wonderful dc, her Grandchildren, was the end for me. She blanked out my awesome (then) 13yo dd who had done a reading in the ceremony - by comparing my dsis's step children.
I can't see another situation in which I'd have to see my mum. I'm very glad of that!