Such a tough spot to be in. I've been there and it was not good... I think the best thing is to be true to yourself. This means telling her who you really are. Either she will accept you for it, or not, in which case it is not really love, and both of you in the end would be unhappy, you continuing to question your gender identity, and her likely feeling you are always holding something back or you do not fulfill her perception of the "male" role. Some of us have been married in the past, even had children, but the gender identity is always there and you will have to eventually face it. I wish I would have seen this earlier on, prior to the hurt I feel I caused, and the pain others could have avoided had I chosen differently.