Is it realistic to purposefully look for a person of your nationality?

Hi, welcome!

I think when we look for a spouse, we want what is most familiar to us. I think ultimately this is what builds a stronger pair bond between the two people. We also subconsciously want our offspring to resemble us, which most likely happens when you make a child with someone of the same race. This is especially true if you're the type that takes pride in your heritage, or wants a sense of cultural continuity (e.g. you want your child to learn your traditions, language, etc.), and/or want to to pass on genetic traits of your ancestors to future generations without it becoming mangled with different traits from other cultures.

It's not racist to feel this way or want this for yourself or future offspring!