Fights were more common for couples in three- to seven-year-long relationships than for those 21 years or more. That makes sense, of course: one would hope that if a couple kept arguing about the same topic for years and years, they'd eventually give up the fight -- or the relationship. This particular study doesn't say anything about the reported happiness levels of the couples, though, which I would like to see before drawing any conclusions. I've always wanted to know if my high school health class teacher was right about how it's not whether a couple fights or not, it's how a couple fights.
If you two just made things official a few weeks ago, the holidays might not be the best time to introduce him to your parents, let alone your entire extended family.
If he feels uncomfortable doing Christmas dinner with a bunch of people he's trying to impress, let him off the hook and wait for a more appropriate time to introduce him to everyone.