Why did he say this to me?

Your situation sounds really familiar to mua. very very familiar, I came across this too. This guy most probably have depression like one i know of. He can be really sweet and caring but tends to criticise you alot for no particular reasons. He can also be over-possessive and paranoid at times. Well, i think you should confront him. Although the one i knew apologises for every mistakes and promises not to do it again, he still does. I'm not really sure how you prefer to handle this situation. It's really up to you to see if you can overlook them and forgive him. All the best!