Well, this should be an easy one. I don't have one. I am single. Totally, thoroughly single.
That isn't necessarily a bad thing. As with most women in my age group, I have spent my entire life taking care of other people. It is an integral component of my character. It also resulted in putting myself last for not just years, but decades.
I guess I would say my current relationship is with myself. I am spending more time doing things I enjoy and I am re-learning my own happiness. Taking care of yourself is not a bad thing. I have noticed, particularly among my friends, that we are slowly emerging out of "someone's mom" or "someone's wife" mode and re-entering our own identities.
I think that may be one of the blessings of middle age. A number of the obligations and paths of our younger years have been completed, transitioned into lesser needs, or vanished completely. This is our time and we are learning to embrace it.
So yes, my current relationship is with myself. That is not to say that I am not open to a new relationship; but that the next relationship will fit into my life rather than the other way around.