Because it needs to be awesome for that first part - it needs to be awesome, because when you’ve been married to that person for twenty years and you have four kids, that’s when it can be less than awesome. You yell at the other person because your kids are keeping you awake, and you’re tired and grumpy and you hate the way they drink beer when they could be doing something useful. But you need to be able to say, “Hey, remember how awesome it used to be? It’s not too good now, but it was awesome once, and it’s going to be awesome again. I love you, okay?”
That’s the problem with people’s relationships these days - 17 year olds are acting like they’ve been married for twenty years, and they’re playing manipulative mind games with one another. Just let it go. You’re young, it has to be awesome, and if it’s not - you need to find a relationship that is. Awesome.