I need advice, quick!

Me and my now ex boyfriend had a argument he said some things that really hurt and I just fell back from him. I never would’ve thought that he’d say these things to me. Anyways, I guess he told his mom about it and 5 minutes ago she texted me and asked if I can talk. This isn’t the first time he got her to talk to me. I didn’t text back yet because I honestly don’t want to talk about it and I don’t want to come off as rude if I say so. Please help me. I wish he’d stop telling her our business because i’m not sure if he’s even telling the whole truth, and has his mother thinking i’m overreacting. What do you guys think? I’m 20 he’s 21. I don’t even talk to my own mom about these things and I don’t really have anything to say to his mom. She’s a nice lady and all it’s just I don’t feel like going through this with her.