why is my boyfriend afraid to show our relationship on facebook?

[Alicia]

I am having a big problem.I am with my boyfriend of one year( we started dating last march) .In the beginning of the relationship he would call me every night and day and keep in touch .Now he goes a few days without even reaching out to me.Since the beginning of our relationship,he told me he did not want to advertise our relationship on facebook because it causes drama,mostly because when he was with his ex, he put a picture of them two and all the girls he had on his facebook wrote rude comments.Now we took a picture last summer and he said he wasn't going to put it up because of what happend with his ex.So since then,both of our relationship statuses on facebook have read single.Its like he is ashamed to show I am his girlfriend.Now also,on my birthday in december,he didn't write me happy birthday or anything on my wall obviously because he don't want people knowing we are together.So today,his ex girlfriend,who he is still friends with on fb,and is married,He writes Happy birthday on her wall like its nothing.And she is his nationality,Russian-jewish.i think he is ashamed that I am not Russian jewish and he still has feelings for this girl>.Why is he afraid to show us off on facebook ? I know it shouldnt be a big deal ,but it is to me.If a simple thing like facebook is too hard for you to show us off on then real life is even worse.He wont even go places with me.What should I do ?