I think I may have overthought this hand (or I just need to trust my instincts more) because I felt that he had a straight (probably with 9-7), but I couldn't shake the feeling that he could easily play an underset or two pair the same way, and that there were many more possible combinations for those hands than suited 9-7's or 7-5's. I was not really afraid of a flush draw at this point, unless it was with an already made straight, because I didn't think he would make that play without at least two pair made.

I pushed on two notions:
1) that he would pay off with undersets and maybe two pair, and that I had better outs against a straight than he would against my set
2) i was committed to getting all my money in, so I might as well make sure that no river card could kill the action.

Anyway, he instacalled and flipped over 9-7, and the river came the fourth 10.