Too nitty or just a good bluff?

Was just playing in a 10p/10p live cash game with effective stacks about £15, I open to 3x from UTG with A10o, folds to the button who is a fairly TAG player and I get 3-bet to £1.20 folds to me and I call. Flop comes A94 rainbow. I check, he bets £2, I call and turn is an off suit 5, I check again, he bets £3.50 and after a tank I fold and he shows Ten7o. I play with this guy a lot and he often tells me how nitty I am, so I know he thinks of me as a nit and therefore I expect him to give me credit for the call on the flop (£2 is a fairly big bet on the flop for this game) My reason for folding is the 3-bet pre, and also that I know he considers me a nit, meaning I think hes putting me on an ace on the flop, and given his 3-bet pre I think hes probably got a better ace. I can see my whole stack going in on the river and Im thinking am I prepared to call that off with my kicker, which at this point is looking fairly weak against the line hes taken. If he hadnt 3-bet pre or if it wasnt my whole stack on the line I would have called the turn and river no question but given the circumstances was this too nitty or is it a good fold? My personal opinion is that either a call or a fold has its merits, he was repping a high ace in this situation and given my read on him (he thinks im super nitty) he wouldnt do this unless he has a better hand. Im interested to see what other people think about this. Thanks in advance.

What happened to you is the exact reason why people are not opening ATo from UTG. And even if you do, you don't call a 3-bet pre-flop.
You play OOP, even if you hit that A, you are never sure whether you are against a better Ax, especially since Villain made a 3-bet pre-flop.

All that being said, I don't think it was a bad fold on the turn. After villain 3-bet pre it is likely he has better A.

Also, if you had AK, would you have made a 4-bet?
I am asking because maybe your range is way to narrow there, In which case Villain may have caught on to it and made a power-play (which he would have done with any 2 cards btw). I can't think of too many hands that you open from UTG then just call a 3-bet pre-flop...

Not to much of a Nit...

As mentioned above, I wouldn’t have opened from the position with A10o... And if I get 3-bet, then I would have folded. Regardless, it was the correct fold as I would have put them on a set after the flop. I know this wasn’t the case, but I think that’s what you would be against with those betting patterns most of the time.

The fact that they are almost taunting you and saying you’re a nit, means that it was a huge risk/ gamble for them that you didn’t have a good hand. If you open the same with any hand, and have a good hand after the flop, then this person who is still raising you will lose their stack.

I’d say, hang in there, play as tight as you want to (I.e. 10% - 15% range, but opening/ closing depending on position) and then stack this person who is clearly just bluffing to badly prove a point.

Best of luck!

It is better to 4bet-fold with ATo instead calling 3bet OOP.
Don't go leveling too much

expect to fold most of the time when you open with a10o - are you just hoping for Broadway? - or a 10h dry board?

A/10 off is mostly a fold out of position for the reason you mention. Your kicker is mediocre. But being heads up, the pros say any Ace is decent. I guess you just have to play your gut, but you now have more information on him.