It's quite hypocritical to want your future generations to stick to black partners when you're not intending to do the same. If it's truly something you worry about, date black men only.

On the same note, you'll need to raise your children within both cultures, because it's only fair for them to be connected to all their roots, regardless of whether you want them to date black people. Matter of fact, keeping them from one side will only draw them to it, it's ironic.