I was shocked at the large number of young marriages among military personnel until I realized that the military does exactly that... providing a decent income and housing for a young man and young woman who want to get married shortly after high school.
The military is far from a panacea but it does provide something in this area that very few civilian jobs can provide which do not require many years of post-high-school training or college.
The military also has to deal with the problems caused by lots of young marriages, including a high divorce rate. There are reasons why marriage has been postponed in modern America and while many of them are bad, not all of them are.
The young people need support and education about what makes a strong relationship, starting (I think this is not too early) at puberty. Some communities offer "relationship and communication" classes for high school students. Going to cotillion and learning basic social graces is another part of it, and some places make sure 10- and 12-year-olds are getting instruction in this. Again, this is not too early to learn. I'm describing a past the vestiges of which still exist here and there.
The military might provide some of the elements but it is also an existence which demands constant moving around in many cases, which would make living in a community aware of the challenges facing a young couple a little more daunting.