In need of serious help!!!!

I’ve been with my bf now for 9 months. We finally were intimate last week Tuesday after 4 months of not having any private time together. He calls me today very pissed. He begins to ask me have I cheated on him and I honestly tell him no. He’s the only one I slept with all year and I was tested negative last October before I met him. I literally go to work and back home. He’s the one that hangs out all of the time. He then tells me I know you cheated my dick been feeling funny since you sucked it last week. I immediately feel insulted. But what didn’t make since to me is that I’ve spoken to him plenty of times since that day and I actually spoke to him earlier today. So how come he didn’t immediately say anything? He waited til the third time speaking to me today to say something. We’re both gonna get tested but I’m sure he’s trying to hide something being how he waited as if he wanted to start a fight. What should I do?