Had protected sex on June 24th, with a possibility that some sperm leaked from the condom (when I took it off, I just thought 'there should be more (sperm) in there'... I filled the first couple of inches with water and it held)... my partner is pretty regular with a 28 day cycle, it was day 14 when we had sex, so she was definitely ovulating, but is now late with her period... it is July 14 and she believes she is having implantation bleeding/spotting... is this possible 16(providing that my sperm survived for 72hours)-19 days after?.

Any time you have sex, even with protection, pregnancy is possible. Even if you use more than one form of birth control, pregnancy is possible. No form of birth control is 100%.

Your girlfriend will have to wait until her period is at least 2 weeks late, then test using first morning urine.

It takes sperm about 2 or 3 days to reach the age after having sex. No form of birth control is 100 percent, condoms based on Planned Parenthood have a 3 to 18 percent chance of failure as normally used.

Next no you have no ideal when she ovulated, it does not work like that, she would have to be taking basal temp each month and tracking it to know ovulation dates.

Can she be pregnant, yes, now she has to wait for two weeks past a missed period to test.