Vaginal sex is very low risk, even when full intercourse occurs. Most people wouldn't even bother to test for such a brief exposures, because the odds of getting HIV from a one-time, brief event are astronomical.
You can test if you want to, but there's no real reason to do so apart from peace of mind.
Highly unlikely such a short exposure would cause it, but you did have unprotected contact so if you're worried either you get tested or get her tested. Your symptoms aren't relevant to HIV, but they could be for covid, so get a covid test. And her husband is irrelevant, if she's cheating on him with you she's probably cheating on him with others too.
Do i need to retest after 90 days? For confirmation?
Hi i tested negative after 28 days of exposure, alere hiv combo Ag/Ab. Is this conclusive?