Don't get into this if you aren't prepared for any eventuality. Of course, you may be as lucky as I was, but you don't know right now. If you aren't prepared to think ahead, then you are being unrealistic. I know I am sounding like your maiden aunt, and the doomsayers that you have talked to. More power to you.
Family implies commitment.
It is worth remembering that you are laying this on them, too, if they choose to bring you into the family. They may be a strength to you. He or she will be involved too. So will your children. From time to time the awkward question as to whether you should even be searching will creep into your mind.