The "no bread" is actually "no yeast." and is a part of the Jewish celebration of Passover, commemorating the Exodus from Egypt when God told the Jews through Moses to bake their bread unleavened because they would have to leave Egypt rapidly. There are plenty. of non-leavened breads that you could have. HOWEVER, just because he has chosen to follow what sounds like a cult (and I do
not believe that all messianic jews are a cult) does not require that you do so.
You seriously need to get an understanding of the practices and beliefs that this particular group espouses. It will help you communicate with him if you have an idea of the viewpoint that he is being given. Ask if they have any books or publications that detail their beliefs (and practices). I am not by any means proposing that you convert--just that you know exactly what you are up against. It would also help you converse with him if you learn the history behind the various Christian holidays--both the religious history and the cultural history. Nearly any library or bookstore will have books with this information. I would say to use google, but unfortunately there is a lot of inaccurate information out there as well as accurate. You might check wikipedia--it goes through a pretty good vetting process.
Was your husband raised as a Jew? Is he Jewish by birth? Why did he start going to these Sabbath Services?
I will say that you should probably have chosen to celebrate his birthday with him on a different day, since it is obvious that going to the Sabbath Services has become important to him. I do see how the very long hours are stressful to you--going to church for a few hours is one thing, disappearing for 18-24 hours is something else entirely.
Okay, I just saw your last post. I don't believe there is anything anywhere in Jewish religious texts about demons. And the only thing in the New Testament is about casting demons out of people, and is not particularly graphic. Any church or faith that causes children to have nightmares and be afraid is just plain wrong. There is nothing in hte book of Esther that indicates anything about Queen Vashti being told to come naked--rather it is about her being prideful and treating her husband like crap! (Kind of the way your hubby is treating you).