What would you do if you found yourself old in your last phase of life and you failed to be in a relationship nor attracting any one

I know I would hate myself and the whole world for this fate. It would be even worse if someone came into my life at this point and she was fir some reason interested as I would reject her for being afraid of finally being happy and regretting not getting into a relationship earlier, or wondering maybe she is settling down as properly her younger self would reject me as younger women rejected me. I think there is point in man’s life where he decide that this ship has sailed and trying to live with the grief and pain and befriending them