I think the heart tends to win out in the end. (But you do need a willing partner, yeah)
DH is not 100% on board with another - we struggle at times with these two, and the past year has been particularly difficult. Our situation is a bit different, though, in that even if we try, it's probably more likely that it won't work anyway. So I'm weighing those odds in when I figure we should just go for it and see.
In the end, I think you make the best of what you've got - whether you have more or don't. It seems to work out.