Two Christmas' ago, my dad, Runic Wolf, and my brother and sister outed me as bi to my mom. They all knew, but she hadn't picked up on it. She ignored it until a friend transferred her Myspace pictures to Facebook and tagged a picture of me and another female friend making out while drunk. My mother saw this, freaked out to my other sister about how she didn't understand, how she thought she'd raised me right, etc. My mother refused to answer the phone when I called for a month after I untagged myself.
When we did talk, she said that she didn't want to know. That she preferred to pretend that I'm not bi and that I have a "normal" marriage. A friend of mine called it willful disbelief.
I love my mother, so I don't press the issue, but it means that I get alot of "I don't want to know what you do in your house" comments, which makes me sad because we used to be able to talk about everything and now there is this zone of unmentionable stuff.
I hope that things settle down soon and pray that your mom stops being so hurtful.