Sure we are aliens in this world....I believe that. I certainly don't view this world as my real home, and most all the Christians that I've met, don't either. Almost all Christians that I've met even view and describe death as "going home".
But nonetheless, while we are here, we are still to be obedient and "Render to all what is due them: tax to whom tax is due; custom to whom custom; fear to whom fear; honor to whom honor."
I don't see the conflict between the two. As Tim PA pointed out, we also need to show our spouse our love and allegiance...this does not mean that we do not have God as our first love.
Yes, we are in this world, not of it. But, while we are in this world, we are to follow the laws and be loyal citizens of the nation that God put us in, for the rulers are His ministers. (It's helpful to remember that Paul was a citizen of none other than Rome.)
I'm not sure if Paul loved Rome or felt patriotic towards it...If I were put in a way-back machine and dumped there, I certainly wouldn't, but I would still be obedient to show fear and honor to it as long as I was there. But, I view America as having been blessed by God (though sadly we seem to be letting go of that blessing) and I do praise and thank God for allowing me to live here. For me, it's no chore to obey Romans 13:7, I can do so joyfully and that is a blessing from God.
When one looks at it this way, it's almost more of a slap to God to be unpatriotic, if one is living in a nation where one can so freely live out our faith and follow God's commands to preach the word and share the Gospel.