I've been thinking recently about the (semi-awful) phrase 'heterosexual life partner', which tends to turn up in reviews of TV shows where the two (invariably male) leads are so close they practically live in each other's pockets, because to a degree this describes the lead protagonists in my writing, even though they're female, and one's married with a child. They call each other the sister they never had and together they each cover the other's weak spots.

It gets a whole lot better if you drop the totally unnecessary 'heterosexual', and better still if you make that partner_s_, to allow in as many people as are needed, and suddenly we're at 'family of choice', and I think that's a whole lot more healthy a construct than the restrictive 'nuclear family'.