youd have to have me believing he is pretty insane for me to want to call off here. this is a spot where your decision on the turn should prob be pretty much the same as your decision on the river very often. calling twice and then folding the third is prove very costly in the long run, except against opponents where we have a specific read they will give up the third barrel after firing two.  without this read, calling twice and folding blank rivers does the maximum damage to our stack while providing the minimum chance of realizing our equity in the pot vs the ranges of hands hes representing here: missed spades, strong Kx, sets. 

difficult spot, but his river sizing looks like attempted value rather than missed spades to me. would love to have some villain stats here