While my background is different than that of most of you here, I can relate somewhat to the relationship crisis that many transitioning MtF's find themselves facing at one point or another.
Even if a heterosexual female wife knows about some of the feminine feelings that her guy may possess when going into the marriage, she often feels, that it is a phase that he'll most likely loose after he is married a while. Even if she agrees to help him dress up, or role play, she has enough love in her heart for him, that she'll go the extra miles to work it out, and save the marriage. If there are children, she will do just about anything to keep him in the marriage...for a while. Make no mistake though, she'll be feeling insecurities about the whole affair.
If he continues to push his need to be a female, and has to go through the complete process of attaining HRT, she begins to have deep disturbing doubts. Even if she professes otherwise! There is still a spark of hope, that it will not last and he'll snap out of it.
Finally she begins to question her own identity, femininity, desirability, womanhood, and ability to attract and judge men. She her self begins to have her own identity crisis. This is when many will revolt, and threaten the husband that she'll leave him, if he goes through with it. They will argue, cry, and be shaken to their very cores about what is happening to them, as a couple, a family.
She'll be thinking about what it will do to her career, family bonds, peer associations, and other social standings, once it is out that her husband is becoming a woman. The wife often times feels she cannot face the questions, the smirks, the jokes, and general disapproval of the position she has found herself in. Once she'll come to the conclusion, that there is no turning back the clock, and preventing him from carrying this dream of his through...devastation will fill her heart and mind as she is ready to deliver the final coup-de-grace. Divorce!
She has decided it is time to end it...and may or may not offer an olive branch of ongoing cordial friendship to him as they split up.
If there are kids involved, as likely as not, the court will decide what visitation and contact rights he'll hold. If he shows up at court enfemme, he'll probably loose out big time. For the folks whose type of marriage like this ends in divorce, they'll have a difficult time remaining amiable...especially if she remarries and her new husband hates you...
The reality of being a TS MtF and married, is usually never very kind in the end. There's always exceptions to the general rule, and for them that can go on together in some newly formed relationship, that is wonderful, if that is what each wants...
IMO, I find it rather amazing that married transitioning men, would find it so surprising that there wouldn't be problems..
Addendum; SarahR...best wishes and a speedy recovery, for we are all pulling for you. Keep that in your heart. God speed.