Thank you for all your responses. I really appreciate it.
Crystalrose, my husband and I were just married, so he's still very new to the family. My dad likes him a lot, but they still don't know each other very well.
My dad confided in me with this secret, but did not tell my siblings (my mom passed away a few years ago). My cousin told him, and he wasn't supposed to tell anyone else, but he knows he can trust me with a secret, and I think he needed someone to talk to about it.
I agree that I should be able to talk to my husband, but maybe I should ask my dad first...?