Walked out on a date last night. Did I handle it right? What now?

Went out with this girl last night. I wasn't even all that attracted to her when we first met at a bar last week, but her interest level was so high that I just had to give her a shot. Said I look like a guy in her favorite show. I'm 33 and she's 22, which is a bit younger than I'm used to dating. She just graduated and also just broke up with her ltr who she had all through college. She's been somewhat of a partier though, so sounds like she's just stepping on the CC. Even told me she kind of "regrets" not dating around in college.

The interesting thing is that she said this was her first official date ever due to being in such a ltr. She was definitely a bit nervous and awkward, but very much into me. She said she told her mom about me and that her sister said I sound cool. I mean I had talked with this girl for like 5 minutes before, but I have upped my game a ton since last year, and have enjoyed a lot of high-interest women lately. She said she was impressed by my assertiveness, etc. There were enough red flags with this one to know she wasn't the mother of my children though (said her family is just like the one from the tv show Shameless).

Lots of kino from both sides, she was talking a lot and laughing at all the stuff I was saying, really engaged. Said she was going on a cross country road trip in a few weeks to find a new city to move to. Asked if I wanted to swim in her pool later. Sounded like a fwb layup.

One mistake I made was that I didn't have us sit at a four-top as I normally do (sit next to her, not across, for kino, plus more isolated)- instead I opted for sitting at the bar to try something new. After a few drinks from each (this girl was drinking faster than me mind you), a dude sat down next to her. Maybe 45, grey hair, out of shape, had a wedding ring on. He starts engaging her (not us), saying how he's here "on business" and what a cool place this is. Suddenly it was like I didn't exist. Her back was turned to me for at least a solid minute at one point, which is a long time. I don't know exactly how long they were talking but it was awhile and long enough for me to feel embarrassed. My gut was telling me something was up. He wasn't all that interesting as far as I could tell but it seemed to me he was clearly trying to game her and she was responding. I know the move here is to not mate guard and to instead engage the other guy and act really nice, but it didn't work well as she would just engage him more and plus her back was to me. She was interested in his job, which may have been distantly related to her major, I don't remember. He was laid back and said, "Wow your first date?" Then he looked at me and said, "Good luck on the date," but continued to sit there and look at his phone. "I like Bob" (that guy), she said to me.

I had to go get up for something (long story but I did have to leave her for a sec), and when I came back they were talking again. She engaged with me again for a bit. We were about to leave and I went to the bathroom. When I returned, one of them was handing the other their phone (don't remember which). I casually said, "exchanging numbers?" as I paid the bill with the bartender. He said, "Just facebook." I said, "Not numbers?" She looked at him and said, "We could do numbers." Just then I had paid the bill. I said, "Well, I'm taking off. It was nice to meet you, have a great night" as I gave her a hug. She said, "What..? I can't tell if he's being serious" (as if she was speaking to him). You have to understand that I said the following super chill and smiling, not agitated at all. I said, "I'm being one thousand percent serious. It's totally inappropriate to get another guy's number while on a date with someone else." I then shook Bob's hand, still smiling and chill, but firm and said, "Nice to meet you, Bob." Bob was smiling, with a pleased look and said, "It's just professional." I, again, very chill, said, "You should hang out with Bob, he seems like an upstanding guy. Have a good night." Then I walked out.

I've never been in a situation like this. Did I do this right? How could I have handled it better? Reading what I said at the end it sounds really butthurt but I was not giving off a butthurt vibe at all. She sent me the following text 15 ministers later:

That was a terrible way to get out of a date and I'm so completely confused right now. I was having a LinkedIn connection with that guy

The thing is, I actually kind of think she acted out of millenial naivety and that she was genuinely interested in me. And that maybe she was so comfortable with me that she didn't mind talking to this other guy. But She didn't act that way and I needed to show self respect and that that was not acceptable to me. She wouldn't turn her back for such a long time to Brad Pitt. Was I too harsh? Did I overreact? I still haven't responded to her text- what should I do now? If she's still really into me I wouldn't mind plating her if doing so doesn't sacrifice my self respect. Or too many red flags? Was thinking of sending her:

It is unacceptable for a date of mine to engage with another guy like that while on an actual date. Offensive and disrespectful. Thanks for hanging out and good luck to you.

Thoughts?