Game: 2/5
Players:

CU = Hero (tight aggressive, had some recent shitty river cards lost half stack, played a few pots passively paralyzed by cards not cooperating @ 100 BB)
(holds 7:hearts:,10:hearts

BU = Villian #1 (loose somewhat aggressive, like to play pots. @ 50 BB)

BB = Villian #2 (in between tight and loose aggressive @ 250 BB)

Note: Hero played a few pots Villian #2 where a 4 outer card hit, and to induce a bluff Hero checked river 2 flush cards. Villian looked at Hero and bet 3/4 pot. And showed a strong hand.

Preflop- folds to Hero raises 15, BU calls 15, BB calls

(45) Flop- 9:spades:, J:clubs:, K:clubs:
Hero bet $25, everyone calls

($125) Turn- Q:clubs:
Hero bet $65, BU goes all in $210, BB thinks for a little while, I look at him intensely, he stares at me and then declares all in. At this point BU and I are friendly, and he whispers to me that he had flipped it, and the Q just ****ed him up. Im suspecting that obviously both players have at least a 10. I was also thinking that one may be free rolling with a flush. Perhaps BB was holding A,10.
What should hero do at this point?

This is EXTREMELY inappropriate, and you should have cut him off when he started to whisper to you.

Well I can’t control everything other players do in a hand. We’ve been playing for 2 hours, never played with him before. And most definitely won’t say anything while we are in a hand. So I don’t see how this comment helps.

You should probably do something to address the attempted collusion by the BTN. You can make a statement to the table that BTN accidentally gave information about his hand, and you don’t want to use that to your advantage — then determine the correct play, pretending BTN didn’t say anything.

If the question is how to best act using as advantage the BTNs unethical speech, the answer is clearly to fold. If he flopped it then half the time we’re drawing dead (BTN has AT), and half the time we’re chopping 3ways at best (BTN has T8). So our equity is less than half of 33%, or 16.5% equity. It’s probably much less than that because BB can have a flush or AT himself.

I think the answer is still to fold without the BTN speech. All too likely that BB has a flush here.

Guess I misread the board. BTN told you he had exactly QT. Which is not giving as much information as I’d thought.
Given that you both hold a T, it biases BB away from a ten and weights him more towards a flush.

OP I think this is a pretty straightforward spot where you just need to shell out a few bucks and purchase equilab/pokercruncher to see what your equity is 3ways against BTNs known hand and a range of hands for BB consisting of the reasonable Tx, all combos of AT, and all combos of flushes that make sense given the preflop action (BB has a LOT of suited combos calling out of the BB). Then compute your pot odds given the price of the all-in, and see if a call is justified.

Guessing it’s a fold cause BB is gonna have a flush or AT at least half the time here.

If you plug in ranges on pokercruncher and make the EV calculation you’ll find that calling the all in is about -$200 in EV. Lol, not close. For the ranges I plugged in, pokercruncher says you are chopping 3ways about 36% of the time and losing on the river 64% of the time. Your equity is 12%. BTN has 18% cause some of his QT hold a club. BB has 70% equity.

The calculation is a bit complicated cause there’s a side pot and a main pot, and you (hope to) chop a different amount from each (1/3 of main, 1/2 of side). So you cannot simply determine pot odds by the usual formula.

When your image is crap (you lost a big hand and are playing passively), T7s just goes into the muck pf. You may believe you are a TAG, but nobody at the table thinks you are.

As played, you've been pushing you hand and got raised on the turn. Since you are not even drawing to a pretty good hand, the correct decision is to fold. For your long term results, the worst thing that can happen is you'll win this hand.

Wow. That’s super interesting! That much -EV?
I’m gonna invest in one.

I ended up making the fold right then and there. Thinking that at best I’d be chopping, and at worse losing to A,10 or a flush draw hit on river when one of the player freerolls with the made straight.

Yes that’s correct.
The end result was:

BB shows J,10
The other guy shows Q,10

Preflop standard open, but basically bottom of your range. Flop I just check. Our draw isn't very good with no nut outs or backdoors and the board is better for BU's range. He has tons of stuff which connects well with this board and isn't folding too often.

Turn bet way smaller or check. Hard to get action from too many worse hands for this size when you're still three ways and there was flop action.

This is a super trivial fold to BB's jam. Don't call for 1/3rd of the pot.

Edit: Actually don't like betting at all on the turn. Our hand isn't really that strong and you don't want to re-open action for BB who has lots of flushes. You can call a reasonable river bet or bet yourself if it checks through.