Step Families Support Group
Traditionally, a stepfamily is the family one acquires when a parent enters a new marriage, whether the parent was widowed or divorced. This community is focused on many of the relationships and issues that may arise within stepfamilies where you may find answers from some members and you may help other members with their questions.
Your MIL is part of the problem but your husband is the biggest part. He has allowed this to hurt you for so many years and that's not being a good partner. Carefully pick yourself up and concentrate on being the best person you can be - with or without him. Then ask yourself whether it is better to have a partner who hurts you or no partner at all (at least for a while).