By the time the river rolls around and you have a paired board with a flush draw and your kicker is weak you have to figure you're beat. Only way I bet into this guy is if he has shown a tendency to show down really weak hands. By the time he re-raises you all-in the pot is so big that you had to call. I would have check/folded on the river to anything except a very small bet. I would also be very surprised when he showed a flush because he called the original bet with only a backdoor and possibly a pair (confused about that part).