Teen’s wish for autonomy on Shabbat causes tension

My wife and I don't consider ourselves very observant Jews. We belong to a synagogue, but don't attend very often. We are religious, however, about our Friday night Shabbat dinner. Ever since we had children, we made a commitment to always lighting candles, saying blessings, and eating together as a family. We've always worked to make it a special time. We often invite our friends or the children's friends over, and we usually had a lot of fun -- until this year.

Now our oldest son is 15 and saying that it's not fair that we don't allow him to go out on Friday nights. He won't let go of arguing with us, and it's starting to create tension between me and my wife, who is starting to feel bad about how we are depriving our son of fun. She's still with me on principle, but I'm afraid that pretty soon, it's going to be two against one, with me being on the losing end of the debate. Any advice?