There is no problem at all regarding religion.
But there are tons of social problems and even biological.
Miscegenation
Take her with you to Divine Liturgy and see how she feels about it. Remember we are only voices on a screen. Best advice would be from God and your spiritual father.
I try to make the case from a simply Aristotelian angle that miscegenation is sinful. I hold that it is sinful because it does not promote the good of anyone involved. Statistics show that miscegenation causes less marital satisfaction, increased instances of divorce, higher likelihood of domestic abuse, the children are born as a unique mutt breed so that they can't identify with *anyone* in the world because nobody looks like them, the children have an increased chance of alcohol and drug abuse, and they have a higher suicide rate. There's really no argument to be had for miscegenation being morally good or even morally neutral. The statistics do not lie - additionally, there are occasions in the Bible that would suggest that God does not approve of miscegenation. I.e the descendents of Abraham being constantly instructed to find wives within their tribe, the Lord purposefully creating the nations and the peoples of them, and in the book of Tobit it is even more explicit.
I would also modify my position to state that two ethnicities within a single race miscegenating is less detrimental and therefore less sinful than interracial miscegenation, because ethnic groups within the same race are more similar in many respects and therefore reduce the risks.
For you, OP, you have a case of lust. You do not love her, you merely fetishise her. You cannot marry someone you fetishise, especially since you understand the statistical consequences. Also, a marriage is invalid if you're purposefully going to not have kids and especially immoral if you use contraceptives to do so.
You didn't establish how it is sinful. You may disapprove of it, but you will need try a little harder to show how it is inherently sinful.
Did you even read the post? Anything that is degenerative or is not ordered towards the good of man is a sin.
You primarily mentioned statistics like someone raised on Zig Forums would. Yet without sourcing those statistics. Again you have not demonstrated how it is sinful. Statistics alone do not indicate sin.
Go find the girl you want to have children with.
Great posts by most people. Just wanted to give you credit
His argument flows from natural law. I would add onto it by claiming that it also is adultery (to make worse) since the specific act of coveting another man's wife is mentioned in thou shalt not covet. Where adultery comes from the base word adulterate which is to mix materials like Iron and clay together.
OP, if you loved her you wouldn't give a shit about what we have to say or make this thread. We all have demons that plague our minds with lust and whatnot. Know them however and their effect on you so you can counter it.
This is a really pastoral question, OP. You should just ask your priest this, instead of asking strangers online (most of whom aren't even Orthodox).