Q: When is the best not good enough? A: When your wife gets HIV infected.

In this study, out of 171 couples who consistently and correctly used condoms, three wives became HIV infected from their husbands who had HIV; eight out of 55 who used condoms inconsistently became HIV infected; and eight out of 79 who never used condoms became HIV infected.  A. Saracco, et al., "Man-to-Woman Sexual Transmission of HIV: Longitudinal Study of 343 Steady Partners of Infected Men," Journal of Acquired Immune Deficiency Syndromes, vol. 6, no. 5, 1993, p. 499.