I’m right there with you on this. I truly think I will never have a child and as of now at almost 30, I hope that’s how it goes for me.
I don’t hate kids, I’m quite good with them actually. I think I just enjoy living my life on my terms and not feeling pressured to do what society expects. I do not think that makes us selfish.
As for being lonely, I don’t think so. I never feel lonely and prefer living alone. As long as you’re a social person, you will always be able to have interactions with other humans out in the world. Then come home to a quiet and tidy home where there doesn’t have to be any rules.
I look at it this way as well. I hang out with my pals almost every day and most of the time I want to go home and be alone a long time before I actually do go home. :)
Sounds like you're living your life on your own terms and it is enough to keep you pretty happy. That's how it's done my friend.