I'm willing to bet he knows his mom knows. I'm from a Muslim family. I know my dad loves beer, my brother knows, my mom knows. My dad knows that we all know he drinks, but he still never does it around us. I'm in my late 20s and have never actually seen him drink.

Drinking is taboo in Muslim cultures and most Muslims who drink won't don't it in front of their elders or relatives out of respect even if they know everyone is aware of their drinking.

That said, I think OP should be allowed to drink in her own house if hiding her drinking at home wasn't something she agreed to beforehand to keep the peace. My SO is from a different background and when he asked me out, I basically immediately hit him with all the cultural rules so he knows what he's potentially getting into because being in good terms with my family is important to me. This included not drinking around them in any context and he's okay with that.

So I'd say NTA if OP wasn't thoroughly made aware of the extent to which these cultural/religious restrictions would apply before deciding to make her life with this man.