I have seen it said before, though I can't recall where, "I am single because I choose to be single."
Well I am single, but I am not sure I would happily CHOOSE to be.
There is a distinct difference between being single by circumstance and being single by choice.
I don't believe that humans are built to be single, to be on their own. Yes, it can be argued that you can be happy and be single - and I don't deny that. Surrounded by friends or family or both, one can happily go through life never feeling "lonely"... one remains ALONE though.
I believe that it is everyone's want to have that one person that they can share things with. Intimate moments - not physical moments, but emotional moments, special times, precious memories. I don't think that humans were built not to have this type of relationship - you may not be religious, but there was Adam and there was Eve - 2 people, not just a singleton...
So why "choose to be single"? I don't believe that.
I think that this is an excuse, a cop out, a capitulation.
I think that when someone (and I include myself in this) says they "choose" to be single, they are saying they are either to lazy or too scared to get into relationship with another. I suppose sometimes this can be fair enough - after a long relationship, a particularly painful experience, but in the long term, choosing to be single it giving up on being in a relationship.