<human>: Can you summarize the given text in a few sentences?

I've been in an on and off relationship for going on three years now. Tonight, he said he was going with his roommate to hang out with two girls. Let's call them Lisa and Amy. Back a few months ago when we were broken up, he started talking to his friend Amy's good friend Lisa. They talked for awhile and he took her out on a date. According to him, things went great, but afterwards she acted like a "bitch." So that didn't work out. 

Flash forward to today, he says "[my roommate] and I are going to drink and hang out with Amy and Lisa tonight." Now, he's hung out with them before, but now that we're for all intents and purposes together again, I let him know that it bothered me. I asked if he would be upset if I hung out with a guy that I talked to for a couple of weeks while we were broken up. He replied that it was different because that other guy and I were talking for two weeks and he only took Lisa out once. We argued because he said I didn't trust him, to which I replied that it wasn't about trust, I felt it was more about mutual respect. He then goes onto say that he hasn't even spoken to Lisa in months. But I don't understand why then he didn't say, "hey we're going to hang out with Amy, but Lisa is probably going to be there too." if he hasn't talked to her. So, I have a couple of questions:

Should I be concerned? Is he right and am I just "being extremely difficult," for expressing my unease? 

I need an honest, unbiased opinion. I figured Reddit was the best place to go.
<bot>: SO is going to hang out with a girl he dated previously tonight, but admitted that if the roles were reversed, he would be upset. Should I be?