I hope that your son takes full advantage of all the opportunities offered to him in college life and does not cloister himself away with his girlfriend, shunning activities that will add breadth to his college experience.
I would adopt a supportive attitude about his choice of college, telling him that you will respect his choice until he gives you cause not to honor it. Your wife should know that she contributes nothing positive if she maintains a disappointed, "you're only going there so you can be close to your girlfriend. You don't fool me," attitude toward your son.