He's not aggressive in bed, seems only mildly interested?

Hi,
There are several possible reasons to it.  The most frequent is health.  Is he healthy ? (Diabetis ?).  Is your husband aware to the fact that you like him 2B more aggresive ?  If yes, what was his reaction ?  If you don't know the reason than discuss that matter with him.  Have a deep & open discussion.  Start by telling him you love him, that you want your relations to flourish, and then tell exactly what bothers you.  Finally tell him you'll appreciate if you (both) find a way to improve your sex.  If you can't reach a solution (or you can't make such an open discussion) than it's a good idea to get a marriage counseling. 
Best regards,

Sounds like a hidden interest - either theres another woman or he may be interested in a cock inside him. 53 he's in the prime of his life and that headboard should be having the neighbors banging on the walls--WILL U 2 KNOCK IT OFF--Thats if he's still into U + you dont have a problem doing those little nasty thngs he like to do. Dr Oron was right sit him down and find out whats in the back of his mind that he's not telling you !!!                  P.S. I bet his buddy knows !!!