Here is the verse which covers many associations, not just marriage. But it especially applies there:
"Be ye not unequally yoked together with unbelievers: for what fellowship hath righteousness with unrighteousness? and what communion hath light with darkness? And what concord hath Christ with Belial? or what part hath he that believeth with an infidel?" (2 Corinthians 6:14,15)
The Muslim is the infidel. True.
Have her watch “Not Without My Daughter” starring Sally Field. That is her future. When Elian Gonzalez got sent back to Cuba there were 11,000 “Letters of Concern” sent to Muslim countries by the State Department on behalf of STUPID American women whose children were taken by their Muslim Husbands.