crappy sex till the end ?!?

Hi,
thanks for the cents (sense ÖÜÖ)
I hadnt thought about leaving him but I HAD thought about taking on a lover- and have threatened, (the response from him is just as bland as the annual boring man on woman meeting) There is another thread about this answer to crappy sex. What else can be done?? I wonder if there are any stories out there about people who have been able to 180 'marriage sex' or any partnership in a good way. Or is it the case that if the chemistry isn't there, it won't ever be