After getting a long text from who I didn't expect

It's been almost a month for me. He made stupid excuses from his work circumstance, even his family, and lied to me about his cheating on me. He really thinks all of them didn't go noticed, and I am so stupid. I knew everything already, but I didn't let him know because he will be the one regrets all day long about what he has done to me. I knew this was going to happen. And the end came with his stupid excuses, and I just remained silent. I just let him go. Literally. Because I was so insecure about all of him. I've never expected he would try to contact me in the future.

Now he texted me again about a month later, and I'm losing my mind. Can't sleep, can't eat. I feel like I'm sinking into the bottom of 'a month ago' I do ask myself like 'what if all he said was true?'.. I'm not sure I can get over from this situation anymore. I might start to believe him later.. but I will try not to believe him as much as I can. Hope this depression will end.