wat was your exposure? a typical 4th gen hiv test only had a 28 days window period.
If your partner couldn't bear an erection there would have been no possibility of sperm accumulation in the condom.
Also, assuming the condom was already used once for a full episode of intercourse and yet there were penetrations post that with out removing it. In that case, sperms can't leak in to the vagina through the ring of the condom as the penis was flacid.
There were 2 possibilities:
1. Either there would have been no penetration.
2. Only some part of the penis must have been inside the vagina with the ring at the base of the condom sticking out.
There are no scope of pin holes or defined tears at the tip of the condom for it to leak, if the condom fails, it is evident.
There was no risk associated with this incidence. There are no scope for 'What-ifs", no testing warranted.
Please use condoms correctly and consistently for all episodes of vaginal / anal insertive sex to stay away from HIV and other STIs.
Considering, there was penetration post ejaculation, penis should have been flacid - Only the tip of the penis covered with condom must have been inside the vagina and the base of the condom must have been outside, if there was semen accumulation inside the condom, it would have not spilled inside the vagina but only outside of it. It is not a risk.
To sum up every thing, you did not have a risk. You do not need to test.