Am I responsible for my husbands misuse of his mothers money.

My husband and his sister are P.O.A of his mother, my husband is joint on a bank with his mother, and he used her money for a line of credit, it was paid back by a mortgage on our house, only it was paid back to my husbands name in a GIC. His sister used over 100,000.00 of this money and he used around 80,000.00 of it. My husband is now living with another women, we have no separation agreement, his mother died and now he is telling me that I owe him the money he used. He has used her money for a mortgage on his new house with his girlfriend and has told his sister that she has to get the money from me. He and his sister had used this money and now they want me to pay them what they used, like double dipping. I have copies of all the bank accounts and where the money went and the GIC in his name. He has no lawyer, bought a house with no financial proof of income or tax assessments, we are still legally married.