Anonymous wrote:No or very rarely. Too much trauma, baggage, priority conflicts, and wishful thinking on the part of the two or four adults doing the blending.
This. Beware the wishful thinking, as it impairs your ability to deal with the other problems.
It's just really really hard to force kids together and raise them as a collaboration with their other parents, and their other parents' new partners and that person's kids. It's constant stress and constant effort just to make the logistics work, let alone the emotions. Having grown up that way and seen how even with the best intentions it's really hard, I wouldn't choose it for myself or my kids.