Embarrassed and jealous, please help?

My boyfriend and I have been together for 2 years and we do talk about embarrassing stuff and laugh about it sometimes coz we are pretty close enough for that. But sometimes he just says stuff that really makes me feel uncomfortable. Like today he came to meet me, and (this is so embarrassing,laugh if you want) he saw my armpit hair, I hadn't removed them and he started laughing and I felt so damn embarrassed that I wanted him to go away asap,and could not enjoy our time together, and I kept quiet most of the time. And then there is this girl he talks to and I saw her messages on his phone, and his messages to her, one or two quite late at night, and I started feeling a pang of jealousy that did not go, and so it ruined my mood further, plus his friend called him and he knew my bf was with me, and started teasing him, by linking him to that girl and then my bf is like oh no man, she left me (refering to that girl). :( just as a joke, so that i get pissed off but I am really feeling posed off since then. Now is this Normal? Coz I know he is not cheating but it hurts me that he is close to some other girl as well maybe. How do I avoid this? He was kidding so as to annoy me but then saw their messages and they even go to school together and I am in a different school. And when I ask him about her, he acts like he does not even talk to her much.like WTF how cn I stop feeling this way?