When I got together with my partner, his daughter was 14 and he had full custody of her.  She demanded that I not look at her, speak to her, or 'bother' her in any way, and I was not allowed to go on the side of the house that she occupied (which got absolutely filthy, but not my problem), and my partner agreed to most of her demands, no matter how much it actually damaged the family dynamic and hurt me.  I was hurt and baffled by the rejection and disrespect for the first couple years and kept wondering why I was not given a chance at all, but it made disengaging sort of the natural state