I think my mates wife wants to shag me!

I'm in a sticky situation and i'm not liking it, it all started on Saturday night when i went out for some beers with my mate (best man at my wedding) we watched the Boro lose to West Brom and had a decent skinfull, we hit our local town and bumped into his wife and her mate towards 11pm ish, now my mates wife is always very flirty, chatty and a outgoing type, but in my eyes not one bit attractive compared to the wife, fuck compared to any half fit bird! Anyway where having our usual chat (the 4 of us) about gossip, beer and anything that came into our head, i'm chatting away to her mate been friendly etc etc, and i feel my arse getting pinched, now i know its my mates wife, she always does it, so ignore her and carry on talking to her mate, next i feel a hand reach round and grab my tackle, this makes me jump a little as she's never been this forward, i turn round and say a jokingly 'Dont touch what you can't afford!' She laughs it off! Now roll on hour or so, and we've moved pubs and i'm left holding my mates pint as he goes to the toilet, i'm stuck with his wife, and her mate who's playing with facebook on her phone, i then feel another hand on my package, i look down and its my mates wifes hand is pulling at my flies, she's also staring straight at me, so i step backwards quickly, the rest of the night i'm doing my best to avoid her, either by talking to other people i know, or her mate , or position my mate sandwiched in between us. It was getting late and i had craving for food so we all moved to the nearest pizza shop, them 3 are ordering pizza's, so i make a quick choice just for a kebab as i'm expecting it to be served quick and i can escape before there pizza's are made, luckily we live in the opposite end of town from them. Whilst waiting for what seemed to be the longest kebab maker in history, i'm invited back to theres for drinks which i strongly decline, giving some excuse i'm wrecked and want to get home, so i say my goodbye's, and for some dumb reason exchange facebook contacts with the wifes mate, DAM IPHONES!!!!
Anyway i get home safely and just brush the experience off as her being pissed and me over reacting to her fun. But today i made the fatal error by excepting mates wifes facebook friendship, and a couple of hours later i'm in even more shock to get a private message from mates wife, basically saying the offer of no strings attach sex is avaliable whenever my mate is away with work (which in Mon-Fri) GULP! How weird is that? Now i have to either ignore it or tell my best mate his wife is a cock hungry whore (his first wife was the same, and it nearly killed him when he finally came to his sensors!)