At your age, the costs aren't theoretical. They're real. Years of emotional distance in a marriage. Opportunities for intimacy that passed because you were somewhere else in your head. Conversations you didn't have because the secret was always in the room.
Maybe it cost you a relationship. Maybe it didn't, but it hollowed one out. Maybe no one ever found out, and the cost was entirely internal — a quiet erosion of self-respect that compounded over years until you could barely feel it anymore because it became the baseline.
You don't need to catalog every loss. But you do need to look at this clearly, without minimizing and without drowning in regret. The past is information, not a sentence.
There is a grief technique that therapists use for chronic regret. Write an unsent letter — not to anyone else, but to the years you lost. Address it to the time itself. "Dear twenties and thirties, I spent you managing a secret instead of being present." You do not need to be poetic. You do not need to finish it. The act of writing externalizes the regret — it moves from circling inside your head to existing on paper, where it becomes something you can look at rather than something that looks at you. Many people report that this single exercise releases weight they have carried for decades.
The question that matters now is simple: how much more are you willing to let it cost?
The past is information, not a sentence. What matters is how much more you're willing to let it cost.
Write the first two sentences of a letter to the years you spent on this. Not to send — to release. Start with 'Dear...' and let whatever comes out come out.