Hi! I believe I can be of help with this issue.
First, let me say I can imagine how confusing and distressing this situation must be for you. On the one hand your fiance is someone you love and are committed to. After all, you are engaged. But on the other hand you are seeing more of who he is now than you did before.
And this is actually the key to my answer to you that you need to consider and think about. You are clearly an intelligent and capable young woman. And I think you sense within yourself that you are finding out things about him that are not just small, little quirks like you originally thought. You originally thought he had a "leadership temperament". But you are realizing that this phrase is actually a euphemism. Your fiance is a controlling personality. He is a controlling personality.
And I am afraid that your fears are correct: controlling men do NOT get LESS controlling as they get MORE intimate with a woman. The opposite is true. And they do not get less controlling as they age. And they do not get better just with time. And a good woman doesn't help them see the light that giving and sharing ideas and listening to the loved one is great. They improve only with therapy aimed and suited for this problem. And of course, the biggest problem, is that they never think the problem is with them, always with you.
So, I am so sorry that you are in this situation. But I think it's a great blessing that you are young and not yet married and are finding out now. I work with women in my office in therapy and it usually is a few kids and well into their 40s before they realize that they can't take it any more. So you have a decision to make that is not going to be easy.
I wish you the very best!
Please remember to click the green accept button. Feel free to continue the discussion; my goal is to get you the best answers possible. Bonuses are always appreciated! If I can be of further help with any issue, just put "for Dr. Mark" in the front of your new question, and I'll be the one to answer it. All the best, Dr. Mark