Married but Unfulfilled

I'm married to John, been together since we were both 18. We have a nice house, two kids, everything seems perfect from the outside. But lately, I feel so alone. Last week, on our anniversary, he fell asleep after dinner. Tired from work, I guess. So instead of going to bed, I sneaked out and had a drink at a bar down the street. Found myself talking to a stranger there, telling him all my problems. We ended up back at his place, and... things happened. Not just sex, real, emotional connection for an hour or two before he dropped me off. I'm married but unfulfilled.