There is a "morning after" treatment.

If you think you've been exposed, get thee to a doctor or emergency room, NOW! Have your partner come with you if they're willing. You need to be seen within 24 to 48 hours tops!

Depending on the risk, the doctor may put you on a course of HIV drugs for a month or so. Not fun, but sure beats meds for a lifetime.

When you go in, be honest about what happened and tell them you may need post-exposure prophylaxis (PEP) for HIV. It's the same treatment they give to hospital staff who've had a needle stick.

This can also be an option for "we forgot the condom".

You can learn more about post-exposure prophylaxis (PEP) here.