What ovulation predictor do you use and how is the fertile window calculated? If it just calculates off cycle length, that is probably your weak link. If you were temping and checking your cervix and fluid you would have a good idea of O day, and could figure out the likelihood of condom failure, vs having sex too close to ovulation.
Wife to Joe. Proud, tired mommy to Captain Destructive (6/09), Sir Screams-a-lot (8/10), and another little miracle due 3/13.
Trusting God brings life. Believing brings rest.