People have a “deep yearning” for human companionship and all kinds of things. It doesn’t mean they’re ready to go out and accomplish it. Most are not ready at age 18, especially nowadays when (unlike previous eras) people are not financially independent or capable of being financially independent at age 18. A large number are not ready at age 28 and some still aren’t even ready at 38.
My personal view is that we don’t do young people any favors by acknowledging that they have such “yearnings”. They need to get out there and do something practical with their lives and then this other stuff does tend to fall into place as HopkinsReb said.
When I was 18 I dated another guy, who happened to be Catholic, was 19 and wanted to get married as soon as possible and start a family. While he was having these romantic ideas, he was also slacking off at college to the point where he flunked out, had to move back to his working-class suburb, live with his parents and work in some mall shop and he still expected me to marry him. Needless to say I moved on pretty quick. The guy married his co-worker at the shop, they moved into a trailer park, had a few kids and then got divorced.
So forgive me if I see romantic dreams of 18-year-olds with a jaundiced eye unless and until the person takes actual steps to walk the walk of a mature spouse and parent.