Hardly Worth It

So this weekend I hung out with an old friend from high school. I thought it was just going to be the two of us, with a couple of my guy friends thrown in for good measure, reminiscing over the good times over some good German schnitzel and beer.
Boy, was I sadly mistaken.
A few weeks ago I had an unfortunate hookup with a guy that was also friends with this girl from high school. Only, these two had dated. Not only dated, but were together while deployed. Not only this, but she "cheated" on him with her ex boyfriend, a guy that I had set her up with a long time ago, via email/skype/im/whatever, broke up with her battle buddy, and proceeded to marry the guy I set her up with.
This should have ended things, right? As in, she broke his heart, he never wants to talk to her again, right?
This guy is now stationed where I am and when my friend said she was visiting, I asked her about inviting him. She said her husband didn't want her talking to him, so I said "hey, no problem, I won't invite him to our plans."

Cut to last Friday. I was at the train station at 6pm, when she said she'd be there. I get a text from this guys' phone saying "I'm going to be late." First thought was "creepy, I didn't invite him anywhere." Then it hit me. He was with her. I finally reach her via his cell phone and she said they haven't even left yet. She is stationed about an hour from me, meaning she would miss the dinner reservations I had planned, as well as a good portion of drinking we were about to do. Not only that, but she was somehow with this guy, even though her husband didn't want them together.
Something felt fishy to me. I told them I'd just meet them at our old high school bar and went on with my plans with the guys.
When we finally met up, it was obvious to me that something was up. He wouldn't leave her side, he wouldn't let her pay for anything, he kept "moonily" staring at her. This dude was totally still in love with her and she didn't have the balls to tell him to back off.
This annoyed me to no end. Not because I had feelings for him. Quite the opposite. I consider him my first "one night stand," even though we didn't have sex, and I quite honestly didn't want to see him again.
This behavior lasted all night long. We ended up all crashing at my house, staying up until 6am. When we finally woke up around noon, I came downstairs to find the two of them sitting together on the couch, with him rubbing her feet like she was some Arabian princess. I'm sure her husband would have loved that.
I ended up making an excuse to not hang out with her for the rest of the weekend. I didn't want to be subjected to the obvious flirting going on between a married woman and her ex boyfriend. I didn't quite know how to react to the first night, so I'm sure after a few more hours of this stuff, I would have blown a gasket.
I truly hope nothing happened between them. The guy she is married to is one of the most awesome guys I know. I just don't understand how some people can be so clueless.
Sorry this post is a random mess, I'm still pretty upset about the whole thing and trying to wrap my head around it just makes me feel sicker than i already am.