To answer this, you'll need to think about how the relationship ebbs and flows. How is this relationship developing? Growing, shrinking, pulling apart, coming together? In other words, the balance involved. It looks like you want it to be a relationship that develops and matures into itself, so as this happens, what is the real reason that it can't? Why is the relationship so strained until the end?
You'll need to decide which of the Elements actually drive this effectively invisible force, this conflict. That will be the Problem, and the thing that allows the relationship growth to come to a real conclusion will be the Solution.
Make sure you're also evaluating the quad as a whole. Many things can be portrayed under many elements, but only one complete quad should feel like it fully balances your intent. That which the relationship believes is stuttering and causing conflict within it should the be the Focus, whereas what the relationship is convinced should remove this perceived problem should be the Direction.
I bring this up because any one of the pairs that you mention actually exists within varied quads.
The stared quads are the ones the contain four of the six Elements you mentioned. It is likely that one of these three belongs to your RS, but it is possible that the RS may reside elsewhere, as well. Take a look at them, and see whether or not they fit.
That's one of my favorite forms! But, I must ask: Can you know that your MC should be Changed, if you don't actually know where the MC perspective exists? Of course, you may very well know this is what you mean to write. It's just something to think about.