When someone you love deeply, starts to tell you bad things about him self.. To stay away from. What

I don't really know how to answer because the stuff wasn't mentioned, if it is insecurity issues then I think he might be just opening up to you. However, if it is dangerous and he's telling you to stay away then I honestly think you should.
You could ask him, let him know you're a bit confused and to explain it. Hope it works out whatever path you go down.