First, welcome to the Forum
Second, many congratulations on finding 'the one' - and all good wishes for many happy years together.
I am sure one of our priests will answer your question. In practice Orthodoxy is a great deal less legalistic than the RCC; indeed, given RCC canon law and practice, any children of your marriage would have to be brought up RCC.
The RCC recognises us as a 'valid Church', but what that means in practice would depend upon the attotude of your parish priest. Although I often read here that the RCC allows the Orthodox to communicate (although Orthodoxy forbids us to), that has not been my experience. You'd need to talk to your young man and his priest about these things in advance.
The Orthodox practice of 'economy' (effectively tempering the wind to the shorn lamb) will, I suspect, mean that there should be few problems on our side of things.
And, of course, what really matters is that your love should be an icon of the love He has for us, and that in your marriage you cherish and nourish each other and, if God is good, any children you might have.
In this is love, not that we loved God, but that He loved us and sent His Son to be the propitiation for our sins. (1 John 4:10)