Rant: Wanting a cigarette so bad, but I'm pregnant.

My SO went out of town with his brother for a concert, I wanted to go but I was never invited despite people telling him to invite me. One of his friends and their SO we're going as well and another friend of his. The one friend ended up not being able to go so she gave her ticket to her best friend, who also happens to be my SO's ex. So he drove up with his brother to their beach house and the couple and his ex met them up there and stayed the night with them at the beach house. He claims they all slept in separate rooms. Then they all drove down to the city a little ways down where the concert was being held. They all got a hotel and he says the friends got one and his brother and him got their own room. Then they all went to the concert and afterwards headed back to the hotel and slept. This morning he texted me and after talking for a bit he told me they weren't leaving yet that they're all going to get breakfast together and then going down to the beach. I've been losing my shit and I'm so irritated this whole weekend I've gotten mad at him for different reasons. I want to trust him but I feel like I shouldn't because when we've broken up in the past and gotten back together I always find out that he was texting her and hanging out with her the whole time we were broken up! He claims he hates her but it sure doesn't seem like it. He even referred to her as an "old friend" earlier when we were arguing. I'm sorry, your EX GIRLFRIEND who you claimed you HATE is your "old friend"? No she's your old girlfriend. Now he isn't replying to any of my texts because he thinks I'm wrong and overreacting that he's spending time with her. I'm so beyond frustrated I almost want to smoke a cigarette I'm so frustrated! Luckily I don't have any because I quit months ago, but I'm just so mad and usually when I feel like this (before I was pregnant) I would smoke like 5 cigarettes. The point is I just wanted to vent. Sorry this is long.