Why do you let your mother and other family members do this to you? You are letting yourself be trashed by people who have personal agendas which have NOTHING to do with your life. That's right, Mom. Nothing to do with YOUR life! Your mother is not you. Your BIL? Where the heck does he fit in here? What you do is not their business!!
Stop talking to them about anything that they will use to denigrate you. If your mom starts this on the phone, tell her that you are hanging up now, and then do it. She is sowing discord in the family because she wants someone to bully. That someone is YOU. Stop letting her do it. If your family members continue it, stop seeing them for a while and when they balk, tell them why.
If you allow them to treat you like a doormat, they'll just keep treating you like one.
Your husband is just as much of a father to his kids as you are their mother. He needs to be with them too. Forget what these people are saying about him watching the kids, and enjoy your PTA work. Stop doubting yourself. It's ridiculous to allow these people to take away your pride.
If your children grow up seeing you happy and fulfilled, working on a "job" (whether it pays or not), they will be happier kids themselves. Whether your family likes it or not, your girls will most likely need to work when they grow up. They need to see you doing that! Your sons need to see it too, because dimes to dollars, their wives will need to work. It's not an easy economy out there and kids need to grow up thinking in terms of having a career. Who better to show them the importance of working, whether it's a volunteer job with the school, or going to the office!
You are not just a mother - you are an example. Show them that you are a strong woman who will not be bossed around by people who only have negative opinions of you. For heavens sake - stand up for yourself!!
Sending you high fives for "I AM WOMAN, HEAR ME ROAR~~~"
Dawn