My boyfriend doesn't trust me?

I've been with my boyfriend for three years and we live together. About three months ago, I went out with my girlfriends and accidentally sent an incriminating text to my boyfriend that was meant for someone else. Although I did not cheat on him, and I would never cheat on him, this text message tainted his thoughts about that. It is a misunderstanding and I told him the truth about what the text meant, and the situation. I was 100% honest and though he was hesitant to stay with me, he did because he loves me. But whenever we get into a fight or anything, he brings it up, which may be every few weeks. But just this week he told me he still thinks about it and it bothers him. We almost broke up when we spoke about it this week and he assures me he will try his best to not think about it, but he has said that once or twice already. He admits it makes him insecure and it bothers him sometimes that he believes I cheated. Although he doesn't bring it up that often, it's often enough for me. I love this man truly and would never do anything to put our relationship in jeopardy, I do not want to lose him and I'm willing to do what it takes to fix this so that he won't have these thoughts anymore. No one is perfect and I made a simple mistake. I have never in the past done anything to give him a reason to distrust me, this is it. I would NEVER cheat on any boyfriend and never have in the past: that's not me at all. He has said that I do a good job when I reassure him in the moment of how much I love him and would never cheat. He even suggested this week that maybe he needs to talk to someone about this insecurity. My bf does not communicate his feelings well, but what man does? I am one who thinks that counseling or anything like that would constitute that we are in a bad relationship. Will counseling help get him, or us past this? Is is worth it?