I'm 31 and if anything I think my drive has only gone up and up and up consistently since about age 12..Honestly, I'd say this might not have anything to do with you. You'd be surprised how much others things come into play-maybe his job, finances or just plain fatigue..It sounds real cornball but you guys should really talk, I mean REALLY talk. I know its easier said than done and you're prob both real busy but I bet it would really help..Then when you guys get back to doing it, it'll prob be even better than you remember (sometimes a break is the best thing!)..