So here's the thing - he was clearly being disrespectful. He knew he was being disrespectful. He intended to be disrespecteful because he doubled down on it when you pointed out the condescension. It wasn't a one-off thoughtless slip.

So there's abolsutely no need for you to hold back (except if your personal safety is at risk). Don't bother trying to be respectful. Why should you give him something that isn't recipraocal?

What to say?

Put yourself first in these situations - Tell him he's being condescending (as you did) and don't take the gaslighting BS he came back with.

No, you don't have a chip, you just don't like being talked down to. No you don't have a chip, youu're just not going to put his feelings ahead of your own.

And no, you don't feel grateful that he respcted your relationship. It's none of his business.