To be married in some churches, one must agree that any children will be raised as members of the church's sect, and no merely as Christians of some sort.
I would not have been allowed to marry my Iraqi girl-friend in a Shi'ite mosque without becoming a Muslim pro forma. She was unhappy that I flatly refused. Her sister, BTW, had a fiance who converted, and then she jilted him. Sucks to be that guy.
Well to be fair Shi'ite islam and Sunni islam are different. As a sunni muslim i would go as far as to say they're different religions because of how different we are, even though we both pray to Allah.
How did you manage to marry her though?
I think its the same for both for christianity or islam whether sunni or shi'ite, that if someone from another religion wants to marry someone else, either we have to convert to their religion, or vice versa. If not possible, than make sure the children pick one or the other.
But, then again let's be honest. Throughout history many muslims, christians, and jews have married with eachother and have got basically no consequences! Especially because muslims consider judaism and christianity as almost "close relatives". And even though technically only a muslim man can marry with the people of the book, lots of women still marry with men of other religions just fine.