Is it time for me to let go?

So I woke up around 12:48 in the morning and noticed that my bf sent me a message. He was at work around this time. The message said "yeah rite." So I was like why did he just send me that message and we hadn't been texting each other in order for him to send that to me. So I texted him back and asked him why he sent that message to me. He called me like a minute later and said that he didn't text me so he asked one of his coworkers(who might i add said that I looked sneaky) did he text me. I was like why in the world would someone that he works with text me a message that said yeah rite. To make a long story short, he ended up being mad at me b/c he said that he hadn't done anything to make me think that he was cheating. During the conversation, I never even mentioned the word "cheating." All I wanted to know was why I received a message from him that he said he didn't send. The first thing that came to my mind was that he probably meant to send it to someone else but he mistakenly sent it to me. Anyway, he got mad and start accusing me of being guilty about something. He does this whenever we get into an argument. He constantly tells me to confess so we can move on. I keep telling him that I have never cheated on him but he doesn't believe me.Someone once told me that love is about knowing when to hold on and when to let go. What should I do?