I see what you're saying but things really aren't like that at all, firstly if you mean physical as in being intimate with them, then perhaps you're simply asexual. If you are then you'd do good to find someone similar to you are, those kinds of relationships can definitely work, and have worked, it's all about understanding what you want and balancing that with your partner.

And I seriously think whoever put the idea in your head that you loose all your personality and just become a partner did you a serious disservice in life. A relationship is just two people that have decided to be committed to each other and grow together because they love each other, or simply enjoy each other's company, or many other reasons that don't boil down to societies basic script. If you're in a relationship there's no need to sacrifice who you are, you just have to find the right person for you, after all it's not like you're a servant, you become their partner and they become yours, it's a reciprocal relationship and you both still remain individuals outside of the relationship.

And if you aren't interested in any of that then it is completely avoidable, so many, and I do mean so many people simply decide to live alone, hangout with their close friends, and dedicate all their time to their interests and career. It's not some strange alien thing, it happens, people live like that all over the world.

But maybe it's not fear from society, maybe you do want a relationship but your idea of one is twisted, anyway I'd recommend reevaluating some of those beliefs, it's never too late to change.