During 30 years of marriage, this has popped up (pun intended) from time to time with us. As Mr. Rackham pointed out, even within our situation, our belief in the culprit leading to this has varied:
A - Mr. "practiced" too much alone to the point that come game time, he could swing the bat without any problems - but the "home run" just wasn't happening. Great for the endurance part, but left the MRS questioning her own abilities.
B - After easing back on the practice, and aging a few years - we found out that if MR delayed his own orgasm too many times, in an effort to make sure the MRS was content, he would lose his ability to finish. It resulted in us needing to alter our play a bit and realize what the results would be from him holding back.
C - Performance anxiety! In situations when we aren't alone and the MR wants to make sure we get to experience our adventures as long as possible and be in every minute - he just doesn't finish.
This is less stressful on the MRS, except there's always the expectation that there will be and extension of the session when we are alone, and she's usually ready for a nap after such occasions.
With regards to our brothel experiences, C is the expected result for us and we've accepted that many of our sexual adventure's are not about a finish (for him) as much as it is the entire journey for us.
When we replay memories of the adventure in our own time - there's plenty of finishing to go around.
