f@, i don't think i worry so much about whether something is mine any more. i think i've given that up as one of those questions that does in fact lead to paralysis.
although i am currently in a stage of approaching that question again, as i ponder grief and where i want to stand in relationship to it, considering cultural expectations as possible pointers for how to deal, knowing that i will make my own (sigh ;) ) decision(s), but still open to what i can learn from others who have dealt with it.
but i think that other people come into this -- as in, i have a number of associations who i interact with at least weekly, and they are like the float thingee attached to some rowboats, to make the boat part harder to tip over. (wikipedia has failed me.) no single one of them has too much say, but all of them together provide some indications that i'm not upside down.