Secret Late-Night Fantasies

I'm married and work from home, which means I get to spend a lot of time alone. Lately, I've been indulging in some fantasies that are quite different from what my husband and I usually do together. Last night, while he was asleep beside me, I spent hours reading kink stories online and masturbating, something that feels both thrilling and incredibly guilty at the same time. Part of me wonders if it's normal to have these kinds of desires when your current relationship is already very satisfying. Is this something I should be discussing with my partner? Or am I just keeping up with a secret life that could eventually become too heavy to hide? What do you think, am I the only one dealing with this kind of tension?