I'm only 26 years old. I've never been married. I've never had anyone I would consider to have a serious relationship before my boyfriend. And...I understand. I understand vaguely how hard this will be for you both. But I also know this much, that if you love your spouse, you can accept this eventually. (I'll call her she as it seems obvious your SO is a MtF based on what you have said.) Love is about long suffering, and caring for someone more than you care for yourself. About being willing to die for them if you really love them more than just a little. I assume that as you are married and profess to love them that you can eventually accept this. I know it's a big step. And I am sure it must be shocking.
You are probably thinking about how she lied to you back then. How she pretended it went away. And lying to your spouse, I can only imagine, is hurtfull. Especially on such a huge issue. And I can see how that must hurt you.And then, you must be hurt that she was never really giving you her true self. Always holding herself back and never really divulging or showing herself.And I can imagine that you might feel that she's stealing your marriage and the happyness, and future happiness. I can see many more, but then my post would take ages.
But also understand your spouses desperation. Those feelings hidden even from you, the person she should have no secrets from. I can imagine her pain too. I don't think she wanted to keep this from you. I can only imagine the pain of keeping this from you. And the pain from the dysphoria wasn't helping. I can sympathize with the daily battle. Trying to repress it. Shoving your inner self and true feelings deep down into your mind and locking them up so tight that you can
almost forget they are there. you can never really forget it totally. And each day you lie to yourself is a day you fail to deal with it. And it makes the depression worse. 2 maybe 3 episodes of depression a week is what i've had. Sometimes crying, and missing half a nights sleep or a full one. It varies. Some people feel none, others feel much more. I have no idea where I am on the spectrum. And then there was likely the effort to hide it from you when she probably needed the emotional support. Just hiding depression is hard and not really effective. To be honest, and I
can not say, I don't know, nor do I claim to know, this is merely a possibility, but I think she might not have been quite as happy as you, not due to you but these issues.
Anyway. I would suggest marriage counselling. It's all i can think of. Also...This kind of thing doesn't go away, if anything, it gets worse. She'll only feel worse inside if she has to repress it, and it'll take it's own toll on your marriage. There could even end up being resentment issues.
I again say this... I do NOT have any authoirty. This is only my intuition and what I could see happening. I am sure this is hard. And if you think we can't imagine the issues, or mroe specifically me, you should know that people in this forum have faced these issues, or will eventually. And I've already told 2 family members of my own gender issues. I know the awkwardness and fear of telling. I would have a nice long talk and say everything on your mind, holding nothing back.
To paraphrase "
The Name of the Wind's Teccam" Secrets of the heart are like stones in your heart. They grow and grow and drag you down. Unlike secrets of the tongue, they don't press to escape and get ot. They grow heavier and heavier and are hard to ever tell. People hoard these secrets in their heart like some twisted treasure. Anyway. I lack any authority or knowledge of your situation other than what you said. this is all my own opinion and suggestions. Feel free to ignore it. I am sorry if any feelings were hurt.