pegging came up during a swap and now i have questions about myself

right so. swap night with friends we trust. me and the other husband ended up in the same room (his wife and mine were busy elsewhere lol) and somewhere in the night his wife came in with a strap and he just... went for it. i was watching and i wasnt expecting to feel anything about it but i did. like quite a lot of feelings. the other bloke isnt someone i thought i fancied but seeing him into it lit something up in me i did not see coming. now ive been home a week and i keep thinking about it. is this a bi thing? a kink thing? both? am i bi or just curious about pegging or curious about being looked at the way she was looking at him. i genuinely dont know how to untangle this and im a bit embarrassed to ask my wife cause we never talk about me being bi cause i never have been before