A few additional thoughts:
- Some people do regret getting married or having kids.
Almost no parent would admit it, but you can deduce by observation that this does indeed happen. So while kids have added meaning to my life, I can see that others may not want or need that in their lives.
- As to the OP, the decision to not get into a permanent relationship or have kids in and of itself isn't much of an issue for me, but I have to wonder why the OP never had any meaningful relationships and also doesn't seem to have any inconsequential or short term relationships.
General rules are just that, general in nature and don't apply to everyone. So I get that the OP may be a rare exception to the general rule that we are social creatures by our nature. But I wonder if there is also the possibility that the OP has some sort of condition that doesn't allow him or her to relate to others very well. If that is the case, I do think that the OP may be missing out on a degree of texture in the tapestry of life that is derived from our interactions with others. So it could be that the OP is perfectly well adjusted, is in full touch with his feelings and just doesn't really get anything out of close human interaction; but if there is something more, it might add something to the OP's life if it were identified and treated. OP may still decide to forego relationships and family, but may derive more pleasure out of other social interactions.
- Having a wife and kids definitely limits the opportunities of most people to do the things in life that they want to do.
I have a good career and have attained some degree of financial security, but I do choose to continue to do a job that I might not otherwise do if I were not responsible for providing my children with some degree of security and stability. That means 2-3 weeks of vacation per year, avoiding big splurges, not paying for big trips, etc. Even with a very reasonable and considerate wife, it also limits my ability to do things that I would like to do alone. For example, I think I would enjoy taking 4 months or so away from my career and hiking the Appalachian Trail. My job will simply not be here when I got back. So even if I could stand being away from my wife and kids for those 4 months, I would not be able to continue to provide them with what I want to provide them.