Is it an affair or is she just psycho

This is about my husband and his companies personal banker. She is a young attractive woman. I don't know her well but the time I've been with the both of them I can feel the chemistry. It's very awkward for me. I can tell he likes her but I don't think he is having an affair cause nothing seems different at home in the last few years.. But I can be wrong.. Anyway my husbands company had an event and at the end there were about 10 of us left so we decided to go to a bar for another drink. She keeps saying how she doesn't drink much and she's had a few already. We get to the bar and I see an old gay friend. This guy is as obnoxious as anyone you'll meet and says the most inappropriate crude thing Sometimes he's funny but it can get exhausting. But it was great to see him I hung out with him for a bit at the bar and he also likes to play flirt hold hands etc.. We were drunk so it was funny to me and my husband knows how crazy he is with all of us and he doesn't really care. Then after I came back from talking with my gay friend she walks passed and says.. Your husband is a good man.. ignore cause it was weird. I go and sit with my husband on a bench and she comes and sits on his lap caressing his neck and telling him he's a good man and how awful I and my gay friend are for playing around and making dirty jokes.etc. I'm shocked and I ask him if what I had done bothered him and he says no. She continues to talk and I get up and walk towards the bathroom my husband follows and I'm pissed. I asked him why he let her sit on his lap he said he was uncomfortable and didn't know how to handle it. Plus her husband was sitting on the other side! This may sound like an excuse to a lot of people but if you know my husband this is truly how he would respond. Then She comes over and I ask her why she was sitting on my husbands lap..and she starts up again about me and my friend and the lewed comments. I said. What the **** do you care if I hang out with my gay friend, what does that have to do with you sitting on his lap?,! She now teary eyed and looking at my husband for support. I tell her you don't get to look at him. You answer me. My husband keep saying let's go.. So I just got my purse and left. So my question is .. R they having an affair? This doesn't seem like your regular drunk flirting. As I write this I think I'm going to get a lot of. You idiot of course they r. But my husband really is not that kind of guy but I guess he's a man and he's getting attention from a young pretty girl so maybe. But also. Earlier that night she saw who she described as her ex boyfriend and when the wife walked away she started telling him how he was her first love and how he broke her heart. It seemed like he didn't even know they were dating.. So I'm wondering if she's a sociopath and thinks she's in a relationship with my husband.