Welcome to HCM.
Unprotected sex carries a high risk for HIV
. At the same time all exposures are not necessarily infectious. There many people remain negative for HIV even after regular sex contacts with their HIV reactive spouses even after years (Sero- Discordant). Moreover there are every chance for your contact would not have the HIV infection at the time of your contact.
your wife is pregnant and would have been checked for HIV. I f she is negative it is well and good.
You also get examined for HIV.
Good luck to you.