Most Helpful Girl
When used 100% correctly (which people don’t do as often as they think) condoms are only 98% effective against pregnancy.
Also, unless she’s temping her cycle there is no way to know when her fertile week is, and based on your description you guys have no idea how to use the timing method to know when to use condoms.
Most Helpful Guy
"She said you can get pregnant once a month two weeks after a period so we have used condoms that whole week and it hasn't broke or anything like that, so it shouldn't be possible that it's by me should it?"
And you didn't use condoms the other times? Brilliant.
Tracking ovulation isn't easy (and no, two weeks after ovulation isn't a good indicator by any means) especially when the woman is young and her cycle can fluctuate from the physiological changes that take place in the earlier periods of sexual maturity.