Can a roommate withhold your security deposit after you break the lease if she also breaks the lease a week later?

by Audrey
(Vernon, Connecticut)

Can a roommate withhold your security deposit after you break the lease if she also breaks the lease a week later?

My ex and I rented together from July 2006 to May 2007 when I moved out early due to her infidelity, thus breaking our lease that wouldn't end until July 2007. One to two weeks later, she also moved out of our shared apartment into a smaller unit in the same complex. Did she technically also break the lease, and if so, should I have the right to my half of the security deposit from her legally? She refused to give it to me regardless of the reason for my moving out early - her infidelity and cheating in our relationship 7 months prior.

Thank you.