Now looking at romance, you can't see how this kind of arc could possibly apply. But it does. Neither of the characters are the farmboy. The relationship itself is the farmboy. And the point is through trials and tests to take it from a weak nothing, to a hero.
Well, the hero part is easy enough to translate, the relationship would be a "hero" when the couple is happy, they are doing well and seem as though they will prosper.
So, what makes a relationship an orphan under the stairs? Well, the people involved could hate each other. That's a common one. Or they could have opposing interests that keep them from wanting to be together. Like she owns a bakery that he's trying to demolish to build a parking lot. Or they could simply not know each other very well.
So now we have where we're going, and where we're starting. The next question is how to get there. Well, what makes relationships stronger? Getting to know the person. Shared suffering. Finding out the person's strengths compliment your own. Realizing this other person brings out the best parts of your nature. And those trials can be the same kinds of events that the farmboy goes through to become a hero.