My new boyfriend is struggling with the huge love we have found in each other

I've been through this rodeo before. I know what to expect with the tears that come simply from realizing you're in love. It messes with each one of your emotions, it makes us re-evaluate ourselves. He thinks he is a piece of garbage that doesn't deserve my love. But he's the most kind, gentle and thoughtful guy I've ever known. He's been suicidal lately. Struggling with I'm not even sure what. I asked him if he's in a state of shock from finding a first time true love in me and he said yes that's exactly what it is. Any of you ever experienced going manic, or getting depressed or anything extreme like that just from falling in love?