Alright...figured I'd throw in a dissenting opinion. Everyone on this thread seems to feel that in no way should a couple marry under the age of like 30. Wow...you've got to be kidding?? Most of us wouldn't even BE here if our parents followed those rules!
I was 20 when I married my wife...she was 21. By that time, we had two kids, and two on the way. (Two sets of twins...go figure! LOL)
I grant that we may not have been 'normal' for that age group...we were both pretty darn mature for our age. We were told by almost all of our friends that we would NEVER last...my best friend called me a damn fool, and told me we'd be divorced in six months. I sent him a card on our six year anniversary...he was divorced then, btw.
We've been married nearly 18 years now. And we've had a wonderful 17+ years, with the exception of a very rough last year and a half. Which, I'd like to add, I don't believe had anything to do with marrying young. It had to do with not knowing how to give our marriage proper maintenance...which almost no one really knows until they learn the hard way.
Don't assume that they're not ready for marriage just because they're young. Take a look at the personalities involved, and their maturity level, and background.
Now, with all of that said... If she's wandering off every few months to find herself, of course she's not mature enough to marry. And yes, he has every right to be concerened that she's not going to outgrow this behavior. Yes, he should worry that she'll continue to act like that if they're married...and he should start setting some clear expectations on their relationship now. If she can't handle it when they're dating, marriage won't make it any easier.
Off my soapbox. Party on, dudes! <img src="/ubbt/images/graemlins/smile.gif" alt="" />