Op ...why don't you define "success"? Ie is it being back for 1 year 2 years 5 years 15 years? ...heck even after a couple gets back after so many breakups to later get married but then say eventually get divorced, THEN what do you call it?
The "happily after ending" didn't succeed In the final analysis did it?
You're focusing IMO on the QUANITITY of time together instead of the QUALITY of time together and the growth acquired by both partners .
IMO you're being unnecessarily judgemental (and I don't think you mean to be so please don't misinterpret me) with the idea underlying your post which is fundamentally about getting back together to stay together "happily ever after".... And if we don't achieve such then we have ''failed'' in some manner ....and this storybook goal is just that IMO: a strongly yearned for myth that while we all want for emotional and social stability, is nonetheless seldom achieved with just one person...furthermore, and for those very rare cases that do "last forever", its not without it blood sweat and tears....but nonetheless its a rarity.
... just because you breakup then get back together and repeat this dance again however many times until your relationship is broken for good should show most clearly that the vast majority of relationships don't last forever and to accept that fact... People change...sometimes couples are able to work through things together and yet sometimes they are not and consequently have to move on, despite repeated attempts of say counselling ...or after detachment and independence gained from prolonged NC ...or after year long breaks and/or reconciliation ....whatever.
Saying goodbye doesn't necessarily mean that we are a failure or that life isn't still wonderful or that we can't grow into better people who later may find better fitting love if we have processed what worked and what didn't ... I know people HATE to accept that reality as it means more painful endings still to come and they look at themselves as failures (and most of us are in pain and denial on this forum) ...but accepting a breakup can also mean more good times ahead once healed and in a more mature inner space.
The flow of life is one of constant change .... many friendships come and go as do changes in our jobs and careers right? Saying goodbye and moving on doesn't necessarily mean its a bad thing from a relationship that is no longer working despite our repeated attempts or wishes either ..''its just life''...simple .
....this post has been VERY therapeutic in helping me realize just how much we cling instead of going with the flow... and also how we can so frequently overinvest in ONE Person for our happiness instead of realizing that love can--and should--come from a multitude of sources.