I absolutely believe we can be happy whether on our own in some form of relationship.
But my approached topic is about our ability to hold unto long-term relationships. If we could, i believe we would choose intimacy with another person over the peacefulness of solitude.
You say it's tiring to be around other people and that's fine, but objectively it's still a personal failing.
If you feel attacked, it's because you also recognize it as such.
You're happy where you are and it's great, but isn't it you're making your happiness because you wouldn't find it otherwise?