Am I a douche for this?

So, I ask, what is it exactly that I should be ashamed of? I am quite certain that I should be ashamed of SOMETHING(S) about the situation... I just don't know what, exactly.

So... I'm traveling for work. I'm staying (for one night) in a nice hotel in an unfamiliar city. Having arrived earlier than expected, I shower, change into some nicer clothes, and head to the bar downstairs for some drinks. I'm not a big drinker, so it didn't take many to get a buzz. I'm also not fluent in bar etiquette, and I think I took someone's seat.

After two drinks, I was starting to feel a buzz and was happily browsing the internet on my Samsung galaxy tab 10.1 (which is excellent, by the way) and found myself in mild conversation with the older (than me, I believe she said she's 41 or so, while I'm in my late 20s) woman next to me. She's also talking with the the guy on the other side of me (closer in age to her, than to me). It becomes apparent that we work in the same industry, and we both can tell that he makes a lot more money than me, but that I am well enough off that I can hold my own when it comes to paying for drinks, etc... (the hotel we're in is nice, but not THAT nice).

As I'm drinking my third drink, the woman (who is attractive enough) continues talking to me in an interested fashion, I mention my wife and our child-to-be a couple times, and everything is cool. Also the guy is interested/interesting enough that we talk a bit. Eventually she brings up the idea of going to a nearby bar that she knows about from a coworker. We (the other guy and I) both go along. I'm not entirely sure why I go, but part of it is, I think, because I don't usually go to bars, and since I'm travelling, I feel like stepping a bit out of my comfort zone.

We get there, talk, and have interesting conversation. She's from another country, and the guy and I are in the same industry, but very different jobs in that industry, so there is ample room for conversation, and it's fun. The other guy orders the first round. He also orders the cigars (I'm also not a cigar person, and know almost nothing about them, but the ones he orders are "okay", as far as I can tell). He also gets the 2nd round.

During all this, I get the distinct impression that I'm being a leech, but I'm both A) again, bad at bar etiquette, and B) starting to get pretty drunk by this point and I'm a bit of a lightweight, so I'm slower finishing my drinks than they are, which means that by the time I think it's time for another round, the dudes already gone off and bought them.

Also, I'm assuming at this point that the guy is trying to get in her pants, and I'm not (see: married, child on the way, bad with women anyway) so I kind of start backing out of the conversation with the idea that I'll just hang out until they're ready to go back, but they both seem to keep engaging me in conversation.

Then, because I'm a lightweight, haven't smoked a cigar in 3 years, and haven't had more than 3 drinks in a night in 2 years, I start to feel ill. I try to hide it for a while, but eventually it becomes obvious. They start saying it'd be a good idea to call a cab, and I go and do that... but by the time the cab comes, I have to go to the bathroom and hurl, leaving a half smoked cigar, and 2/3 full glass of Jack and Coke.

THEN, on the cab ride home, I'm on one side of the back seat, the chicks in the middle, and the guys on the other side... and she start rubbing on my thigh. Eventually it becomes much more obvious, and she even puts my hand on HER thigh (which I then rub, because... well... it felt nice).

FINALLY, after about 3 minutes of leg rubbing.... (I have no idea what, if anything, is going on on the other side of the car, as I'm busy looking out my window), we get to the hotel, and while I'm fumbling for my wallet (desperate to have paid for SOMETHING), she already has her money out and pays the cabbie... I get out the cab and stumble around to the other side... and quickly shake hands with the dude and, before she's out of the cab, act like I'm drunker than I am, and make a bit of a show of stumbling into the hotel, to the elevator, up to my floor, and into my room as fast as I can.

I did make of a point of shaking hands with the guy and, I hope, giving him the go-ahead to swoop in so hopefully they weren't both "disappointed" by the night or whatever...

So am I a douche? And why? Is it for taking some guys seat at the hotel bar, for even going to the hotel with those two while I'm married (with baby on the way), for letting the other dude buy all the booze/cigars and then leaving them half-consumed, for potentially c-blocking this guy, for throwing up and cutting short the night out, for "mutual leg rubbing" or whatever with this chick, letti