Could I ask did your R start as an A or a normal hook-up that had none of the elements that come with an A?
Husband? Children? Marriage?
Was your partner at the time involved in a very bad MR you know what I'm saying there..?
If none of these were present then quite rightly the R would and should last, my above point describes a WS who is fully enveloped in a long term "normal" R.
By the way I'm not saying AM don't last I'm just saying more fail than succeed.
M
DR'ing started March 2017
Don't blow the last bridge up from fantasy island, act "as if".