ok, have you tried watching porn together? I know it sounds a little odd but, if you watch it together sometimes it spices things up a little. and you may want to try some role playing (nothing too out there) just some normal roles ask him some of his fantasy's are and try to fullfill them. try something new like some new sex position or a sex swing! maybe even do a strip tease for him or a pole dance. try to tease him... get him to where he wants you so bad... don't actually have the sex right off wait and do some foreplay. where ever is gets the most turned on by you kissing him do it a lot and just keep teasing that should heat things up a little
hope things work for ya