I live with my partner. I am resident, they are not. We do not have any papers to say we are a couple.
We want peace of mind that ‘should’ anthing nasty happen and one of us is incapacitated, that the other can
act as Next of Kin to carry out our wishes. 
Do we have to be married in order for us to be recognised as each others next of kin?
or can we go to an abogado, and then/or directly to a notary (even though they are not resident) to have
our wishes witnesses and confirmed officially?

Partner has 3 grown up children (in UK) whom I would guess would be first port of call, I only have my parents
(again in UK), but neither of us wants them to be involved in big decisions such as this.

Thanks…