Woman allowed to keep baby secret from father from one night stand?

NO..with a one night stand and the guy reuniting with a different woman that is now his fiance why possibly ruin things with that? I feel that the adoptive parents should be given the chance to give that child a home with two parents that love each other and the child, not to disrupt many lives and let a child know that their birth mother gave them up after the natural dad and her conceived them just b/c they were on a rebound from broken relationships. That isn't fair to that child. Let the child grow up in a home where it is welcome and wanted. Not where it was an "accident" from one night of .