Lisa, you need to step back and breathe....I agree they treated you like .....crud (trying to keep it rated "G") and you want what any rational adult would want. I'm wondering if this just wouldn't bee a good time to step back, let your husband do what he is doing but the more YOU talk the more it will look like a "I was hurt and they are mean."
Okay, your kids just came home to tell you that "Johnny" said they took his kite and flew it into the old oak around the corner but they were with "Johnny"'s brother playing. "Johnny" and aother kids ruined the kite but "Johnny" has already told his Mom on them and his brother is trying to tell their Mom different you get a phone call....what do you do....Lisa, this is the same situation but now we are adults....(you can say that but I can't

) Think of what you would want your kids to do and think how you can work this out for yourself.
Meantime, focus your energy with the teachers you feel comfortable helping, for yourself, away from the PTO. I am honestly enjoying my self impossed break after four years.
Hang in there, you are the stronger person here and know the higher road.