Perhaps his range needs reviewing here. What we know is he"s a decent player. Maybe its premature to put him on a set or a draw and nothing in the middle?
After all, all we know so far is he flatted a raise from the BB and check raised the flop on a wetish board. All we have is a a pair of
with a weak kicker. I think also you"re over 40 BBs deep, and this seems like a very marginal situation for you to be risking all your stack. There"s not alot of info out there to put him on a tightly defined range. The insta raise may indicate a draw but it obviously varies as a tell in different players.
Also, he"s seen you fire many bullets already so could have slipped any number of hands to you on the flop for you to fire at.
In addition he"s just accumulated his chips and we know people are sometimes less reluctant to gamble with a newly made big stack
I"d fold the flop and wait for a better spot where I can get a better read of what he may be holding.