I hooked up with my cousin's husband many times.
When did this happen with your cousin's husband?
I have had sex with him on numerous occasions.
You should not have done that. Sleeping with family members' spouses is a first-class ticket to destroying the family relationship.
It's not that bad and I don't feel guilty about it.
You are cheating with your cousin's partner. This makes their partner a cheater, and is going to make your cousin very upset. Not to mention, it will be difficult for your cousin to trust you down the line.