One technique I’ve tried is to “chart” the RS, making a graph where the y-axis is something like “togetherness” or “relationship fulfilment” (I think intuitively we know what this is even if it’s hard to define). The x-axis is the story timeframe, marked into 4 equal parts so you can see the signposts / driver points.
I don’t think that there’s any particular shape of curve you’re aiming for, though you definitely want to avoid a straight horizontal line! I think the more focus on RS in the story, the more ups and downs you’ll see in the curve. Anyway, the point of this technique is just to see it better, see if it matches your understanding or what you’re aiming for, and help you pinpoint the inflection points where things change.
Note that in this example, the y-value at the end is pretty much the same as the beginning. This fits the story because it was a new relationship (they met in Act 1) and they ended up apart, going their separate ways but without remorse. The points at the beginning of Act 4 below that value are like “we’d have been better off if we never met”.