Search Results: text him happy birthday

So my boyfriend and I have been together two years.
He's from another state, but lives with me in mine. I've always been the jealous girlfriend, tbh. He's had a lot of female friends and has one in particular he had sex with at age 16. He's 26 now. He's told me about her and said that there's zero attraction and would like for us to meet one day. He went back home to visit his family, and when he told me he went and visited her without me I got really mad. I told him when he got home that I want to be there next time, and don't want them hanging out alone because they have a past.
He got upset and didn't understand it seemed, and ended up saying "I promise I won't go see her the next time i go home."

several weeks later we're on the couch at his house and I nonpurposefully glanced over at his phone and he closed the app. I asked him right away what he was up to, and he responded with "I don't want to fight." I finally coaxed it out of him and he told me he got a happy ST Patrick's day text several days ago from her and was just now replying because he hadn't seen it. He said he thought I'd feel weird about it as the last conversation about her didn't go so well. I know they're friends, but I feel weird about this. She's called him before to wish him a happy birthday, and while on the phone with her he said he was hanging out with his girlfriend blah blah.

Its weird because I did tell him I was down to meet her I just didn't them hanging out alone. Am I just being paranoid as shit? or is he up to something?