We too are child less,not particularly by design, simply this is the way "the cookie crumbled" if you catch my drift.
We realised along the years that we are not at all maternal, and yet our two dogs were treated like precious children........but we have simply found the two of us seem right for each other and there is no pressing need.
Having said that my DH always has said I would have made a very caring and devoted "Mom".I think as we have got older we feel the need more of that other certain someone in our lives but,certainly in no way thinking of someone to look after us in our dotage..........simply an extention of ourselves, with the possibility of G/C making a further few little extra faces and personalities.
More so now I am a GN member I am getting quite envious of all of you with lots of family members around you.
Still,that is life and obviously not to be "our lot".
We did get questions and odd little looks earlier on but we were simply open and people soon got the message and changed the subject.