History of cheating comes back

I just found out my bf's fb password today. And he is msging some woman. She blatantly told him, "love you too!" We have a 6 year old together. And this isn't the first time I caught him msging some woman. On May 15, 2017, he was msging an old flame of his. He was telling her how he wished she were me. When I confronted him about it he tried saying it is because of how I been treating him. And I ain't gonna lie after I saw that msg, I looked elsewhere for love. And once I did, he changed his tune real fast. He still blames me for cheating on him. I would like to think it is more like me looking for what else is out there because clearly I wasn't good enough and still isn't good enough for him to love one woman. He doesn't know I know his psd yet so I am gonna wait out how they play out. In the meantime, he is gonna see the b%^&ch come out in me. I feel bad for our child together. Let's just hope one woman is good enough for our son to love. To be continued....