Partner A needs/wants some attention*
Partner B is too tired/stressed/busy to give required attention
Partner A tries again
Partner B responds as above, with a slight tinge of irritation
Partner A tries again, this time with more urgency
Partner B responds as above, now with annoyance
Partner A sulks
Partner B gets resentful
Partner A sulks some more
Partner B gets even more resentful (and thinks to herself 'that sulking thing is VERY unattractive, there is no way I am going to give you any attention if you are going to be a sulky susan)
Eventually Partner B realizes that she is never not going to be tired/busy/stressed and decides to give Partner A some attention. A great time is had by all.
Partner A is very happy and full of the joys of spring.
Partner B thinks to herself - well, that was actually quite pleasant. Why didn't I just give him some attention in the first place! Will I never learn.
Rinse and repeat.
*You are welcome to substitute 'attention' for any word you wish.