Every problem, bit of drama, suffering, torment, or heartache in a relationship is necessary... because people date the people they need to date.
I have a pretty good track record predicting how relationships will turn out.
I can tell, fairly reliably (though I'm sometimes wrong... but not a lot) how a partnership will go after a short time around a couple.
It used to aggravate me, some years ago, how when I'd identify an obviously troubled partnership, no one would listen to me and end the thing before it grew worse.
Time and again, dire warnings to friends of how their relationships would turn out came true.
And still, no one listened.
Yet, these days, people disregarding my advice doesn't aggravate me anymore.
If I see someone headed into an obviously troubled relationship, I will warn him off it.
However, if he chooses to pursue it, it no longer bothers me. I'm not a busybody... what someone is doing with his own life isn't my business, unless he wants my input. I usually won't stay as close with a guy going into a troubled relationship against my advice, because of how troubled relationships tend to affect people (i.e., they turn most folks into needy, emotional messes who bog down everyone around them... and it's not my calling in life to be a shoulder to cry on, nor is it a role anyone would want me in anyway. Really, you are better off not having Chase in that role).
Over time, my understanding of why people date the people they do (as well as do the other things they do) has changed.
I stopped viewing people's choices in mates -- even choices that hurt them, and lead them to suffer -- as 'right' or 'wrong' for them.
Instead, now I look at a partnership and say, "What about this partnership makes it what this person engaging in it needs?"
Because that is the real kicker: people only have the relationships they need to have.
The more you learn to look at relationships as people with exactly the people they needed to be with right then, the more even the very troubled relationships you see start to make a lot more sense.