He's texting another girl

Okay… so I just really need to vent right now. I dunno if I'm just overreacting or being too jealous or what, but… my boyfriend and I had a falling out and after all that we got back together recently. He told me he ended up breaking his friend's heart because he's with me and not her. Last night, to make up, we sexted. Then he spent the rest of the night talking to her until 5am because she "couldn't sleep". I feel really insecure and I feel like I'm crazy.