Quoting KNZ.:" I couldn't do that. My son's 'dad' was never in the picture, and even in my most serious relationship ... [snip!] ... dealing with that 'mom' or 'dad' leaving- doesn't mean it's okay to unnecessarily set them up for something like that. "
I don't see that scenario possible in my life.
I mean, for a child to actually consider and love someone so much to award the "mom" or "dad" title, it has to be something more than a couple of days hanging out or a couple of visits per week/month/whatever.
The affection would have to be mutual. From the friend part, he/she must really feel such strong connection to the child. I honestly don't see it happening with the kind of friendships I have.
I love my bestfriend's kids to death and if they ever needed anything than I'm actually capable of doing for them, I'd do it but I don't think they will ever see me as something close as another mother. I think I'm pretty much like a cool aunt.