I was 23, DH was 25. We will have been married for 2 years in May. we dated for about a year before we got engaged, then we were engaged for 2 years while he was trying to find a job.
We bicker, but we don't have very many full on fights. We also went into the marriage with the expectation that divorce and cheating are not options, end of discussion. I don't like the "don't go to bed angry" rule. I think it works in theory but not really in practice. So, our rule is that no one, no matter what the fight, can sleep on the couch. We both have to be in bed, together. It is hard to be mad at someone all night when they are sleeping next to you.
Also, we still make some time to spend alone, as well as together. I have nights when I go out with my sister or friend, and he doesn't complain, just like I don't complain when he spends time with his family and friends. A lot of people think that once you are married, you should only be around each other, and that everything has to be run by the other person. One thing I think is important to remember is that we were separate people before the wedding, and we still have different interests. As long as our family that we have made is the most important thing, we can still be individuals.