He/she was asking specifically if you could have a BF/GF.
Under the context of a romantic relationship, and as I've said before, having your girlfriend or boyfriend travel with you constantly would probably be a lot like an extended date.
And it's true that (even though not mature enough to understand a relationship) kids at at least ten can have some form of companionship.
Companionship, yes. Girlfriend/boyfriend in the same vein as the original question is questionable, however.
My question to you is do two individuals require a development on a sexual level to be compatible or....?
Considering the fact that in order to get the kind of level of relationship I'm thinking the question is asking about, you'd need some level of awareness of your own sexual orientation/an actual attraction to a certain sex (i.e., some level of sexual awareness), yes.
As a note, sexual awareness =/= knowing what to do with your, well. It means being mature enough to want to spend more than just a playdate with someone else. Kids have crushes, yes, and girls especially throw around the "marriage" word from the time they learn how to say it. It's harder to believe that they'll actually foster a serious, committed relationship with one another because they don't exactly know what one is. So, I just don't see two ten-year-old kids traveling around an entire region and spending more than a fraction of that time considering each other to be boyfriend and girlfriend. Close friends, yes. Wanting to marry each other's a different story.
Besides, if they were to make a game with dating, there would have to be a beggining to it, and not just jump it right off the back.
Naturally, but it would develop from there, one would think, and one would assume that traveling through an entire region would give the player enough time to develop the relationship a bit more.
At this point, it's probably an issue of interpretation of the original question, so perhaps it's best dropped unless we can agree on what level of relationship the OP was actually asking about.
Edit: Also, to clear up the Yakko comment, it was mostly to say kids that age probably know about it or have an inkling about it, but they don't necessarily do anything with that knowledge.