i think when you get that feeling like you need to stop.your wife shouldent stop she should keep riding you or whatever then you would cum and feel even better .just luckley your penis might get used to the way you dont stop when you feel that urge.oh also do you thinbk you might have a kidney stone?
you should try and do more sexual things maybe your doing the same things to often and your not as interested try and switch things up a lttle