heloc dower

My husband took out a heloc on the existing equity in our home 10 days before our divorce was filed, unbeknownst to me and without my signature.

Both our names are on the deed, but only his is on the original mortgage. It is my understanding he would have had to have my signature on a dower for the bank to approve this heloc.

How was he able to get the heloc without my signature?
I have not seen the actual signed closing papers. Would he have had to forge my signature or would the bank allow this?

I live in Ohio.