Peter wishes Liz was here so she could just confirm what he's sure is going on here. He isn't sure why he's second guessing himself. Especially since Tony has all but said it.

"Um," Peter says uncertainly. "How long have you guys been friends?"

He's not sure if Tony is going to get what kind of friends he's referencing while he's like this. Tony seems kind of loopy when he's had a few too many drinks.