I think (IMO) that the 12 month review was put there so that H can come back when it all goes tits up. TBH I cant see this marriage lasting, especially now the Royal bonus has been removed. That's not what M married for - she may loved/still loves him, but apart from being her baby's father he can't offer her much else.
Financially, she'd probably be better off doing a megabucks spillthebeanz to set her up for life. Then she can go her own way and not have these constraints put upon her.
Which leaves H in the lurch - but she's bolted before, she'll probably do it again.
I would desperately hope to be wrong and that they really love each other and are going to live a quiet, happy life, but it's not looking like that so far.