I'd say the seperate bedroom request is a red flag. I agree with the people here who say seperate bedrooms in a relationship can work fine, but I don't think people normally go into a marriage stipulating that they'll have seperate rooms from the get go. Maybe it is nothing, but for me it would be a red flag. Marriage is a huge commitment (obviously), and before he gets into it I'd say he needs to make sure she is commited. Better to find out now rather than waiting to get married and then figuring it out.

Nothing wrong with her needing to get some space and spread her wings, except for the fact that they're getting married in a few months. Doesn't sound like she is ready.