If she is not on the loan(s), it will not affect her credit directly. However, since you will be married, when the two of you try to purchase anything together in the future, your affected credit will indirectly affect her by affecting your combined credit.
Have you considered doing a short sale or a Deed In Lieu Of Foreclosure? These will still affect your credit but not so drastically or for as long a period of time.
But you need to avoid foreclosure if at all possible. Because in the future your situation cold affect your relationship.
Collections constantly calling, possible court and judgement liens in the future. I have seen so many difficult situations because of foreclosure. the stress is difficult on relationships and your health also.
You can avoid this by short sale or even a deed in lieu.
I had a woman call last week to help her after her home was already foreclosed... She is being haunted by twp for taxes, even though she no longer owns the property... HOA is suing her for unpaid fees... Utility companies are calling her... She doesn't even own the property anymore. But she is being haunted. the future implications are yet to come.
Search Short Sales and foeclosure Deals at http://www.BuyNjShortSales.com