JLMS,
The short answer is 'no', however.......
There is a good possibility that you may be trained in the US and may (for various personal reasons) have to leave your wife in the UK. You may have a decent job at the moment and you & your wife will have to get used to leaving on zilch for quite some time. You will have your head buried in books for months and will be flying hard to pass the course, therefore little time for 'normal' husbandy-type stuff.
These are just a few of the consideraions that sinlge people (mostly) don't have to face when starting the TEP course. None of them are insurmountable but you will be expected to have given the implications of the ATPL course due consideration.
In the end it boils down to that last sentence. You definitely can be married and do the course. It definitely will not affect your application but you will almost ceratinly be asked for your opinions on what you're taking on.So make sure the 2 of you think through the scenarios first (for your own good and not just for the interview).
Hope it helps,
Pontius
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You Ain't Seen Me - Right !!