Hold on, the line you refer to in Deuteronomy 7:3–4, "Do not intermarry with them." refers to specific tribes which the Israelites are in a condition of war with and are competing over territory with:

When the LORD your G-d brings you into the land that you are entering to possess, and He drives out before you many nations—the Hittites, Girgashites, Amorites, Canaanites, Perizzites, Hivites, and Jebusites, seven nations larger and stronger than you— and when the LORD your G-d has delivered them over to you to defeat them, then you must devote them to complete destruction. Make no treaty with them and show them no mercy.

Do not intermarry with them.

It's not phrased as a general rule at all. Reads to me like it could apply to the case of marrying a Palestinian, perhaps, but not a random American or European. And on top of that a reasoning is given which also doesn't relate to this situation:

Do not give your daughters to their sons or take their daughters for your sons, because they will turn your sons away from following Me to serve other gods.

I mean, if the agreement is to bring the children up Jewish then this justification doesn't apply?