Sunny, welcome to SR. My A also drank secretly, denied it to me when questioned, and withdrew money from our savings over a period of years to buy alcohol w/o my knowledge (needed to buy it w/cash, as credit card would leave a paper trail). I was so certain at times that he was drinking, but he was leaving the house every Saturday AM to "go to an AA meeting" (which he never went to) and he denied that he was drinking w/such a hurt look and such sincerity....
You are not alone in believing what someone you love tells you b/c you want to believe!
I'm glad you are able to feel detached, and I hope you find support and hope here. SR is a wonderful community. I've also found Alanon to be a great resource and would like to suggest trying some meetings.
Wishing you strength and clarity as you move forward.