Is he scared or ashamed?

So I recently got back with my boyfriend of 6 months after a few month break. It has been going well. We hang out, watch movies, and cuddle at night. We have fallen back into a great swing. Until this week. I just get this creeping feeling that he doesn't want anyone to know. After us being back together for 3 months I decided it's about time to go public. It's not like we are completely new anyway. Well in our society, the social aspect of life is everything. So I proceed to change my facebook relationship and start telling my friends. I am happy to be back with him. I even tell my parents. On the other side, he tells almost no one. No facebook change. No telling his parents. And no pictures of us. I wouldn't be too mad about these, but he decides to take a weekend trip with these girls. As soon as he gets back, there are numerous pictures with a girl on his arm. And to add this girl was the same one we broke up over because they basically slept together all summer. He knows I don't like her. And I'm sure she has no idea about me. I can't decide if he is ashamed or scared to let everyone know about me. I just wish I could be treated right..... I deserve better.