Well, I had the good luck to have two children who were potty trained by the time they were 4 years old, with no regressions when the younger one was born.
What I would like to say though, is that I was very concerned that my kids would have a difficult time, based on my own history. I was a chronic bed-wetter almost until I reached high-school. My parents tried everything, from taking me to the doctor for many horrible tests to ridiculing me in front of my friends. They didn't have pull-ups or adult diapers when I was growing up, so I was never able to experience sleep-overs with my girlfriends until I was in high-school. As it turned out, there was nothing wrong with me, other than the fact that I was a VERY deep sleeper, and could not wake myself up to use the bathroom. I can remember having to be shaken to get up in the mornings (I am still NOT a morning person). As I got older, as is normal, I started sleeping lighter and I stopped the bed-wetting.
I would have to say that those memories are some of the worst I have, and when I became pregnant with my daughter, I promised myself that I would not do what my parents did. I know that my parents love me and they were doing the best that they could, but it wasn't right.
I guess my point is that it is not your son's fault, or your fault, that he is a bed-wetter. It's no-one's fault. Yes, there could be a medical reason for it, or maybe it is stress-related, but chances are, it's not. From what I have learned, it is a more common problem than what most parents think. Don't let it stress you out. In a situation like this, it is always better to affirm the positive rather than focus on the negative.
I don't mean to imply that you would treat your son the way I was treated, but how you handle it can affect how he feels about himself in the future. I know because I have been there.
The main thing is to have patience, and let him know that you love him regardless. Keep doing what you are doing. It will stop.
Happy Anniversary!!!!