I'm sorry about that, I recommend that you tell him the truth about why you're going to break up with him, I'm sure he'll understand, and if not, at least try, you can even find a way to fix things between the two of you, I met a friend who, to be honest, I liked, in short, I screwed up with certain things and I stopped wanting to even be my friend, recently I tried to talk to her by sending her an audio via WhatsApp to meet and talk about certain things, she did not answer me, however I don't regret trying it and it will be one less thing to regret on my death bed, I hope my comment will help you, good luck with your problem, I hope the best happens and you can solve it together.
psdt: I would love to know what happened and see if my advice helped you! Tell me or something if you feel like it, don't feel obligated of course.