New research suggests that women who are ovulating are attracted to their regular partners less, and to other men more if their regular partners are asymmetrical.
Proceedings: Biological Sciences (FirstCite)
Women's sexual interests across the ovulatory cycle depend on primary partner developmental instability
Steven W. Gangestad et al.
Normally ovulating women have been found to report greater sexual attraction to men other than their own partners when near ovulation relative to the luteal phase. One interpretation is that women possess adaptations to be attracted to men possessing (ancestral) markers of genetic fitness when near ovulation, which implies that women's interests should depend on qualities of her partner. In a sample of 54 couples, we found that women whose partners had high developmental instability (high fluctuating asymmetry) had greater attraction to men other than their partners, and less attraction to their own partners, when fertile.