Boyfriend using me for another girl

So last year I had a boyfriend. Let’s just say his name was potato. So potato and I meet through an app called Houseparty. We quickly became friends and eventually started having feelings for each other. Now. Everyone in basically the whole school knew about him rllllyyy liking a girl who let’s say her name is kiwi. Potato kept asking kiwi out several times before we met and kiwi rejected him. So when me and potato met he told me he didn’t have any more feelings for this girl. So I trust him on his word. After that convo. We decide to be more exclusive. Later on in the relationship I hear more rumors about him and kiwi. Of course he lied to me about not liking her anymore. But I’ll save that for later. Next thing I know we are on the field together me and my friends and potato and his. One of his friends them says. U guys need to hug in front of us. But we didn’t because we were a new thing and we were embarrassed. After that I just decided I didn’t want to keep going on like this and decided to break up with him and say I just wanted to be friends. When we break up. Get this. Potato goes to kiwi and says. I didn’t like her anyways. I was just using her to make you jealous so that we can be a thing. And she rejects him once more. THEN. She comes to me and tells me what had happened. And I’m like. Wow. What a fat liar and cheat. Then he goes and starts dating my best friend! I mean wt actual fuck. But I just heard news they broke up. Thank god!