Both of you get tested. Also at the same lab, ask for a sperm-count test. Should be zero if he has had a vasectomy. Then buy a male chastity device like this: https://www.amazon.com/Bondage-Shop4u-Male-Chastity-Belt-Cage/dp/B00BPN2C4I
Boom, now he can't have sex with other women. And you know he is STD negative and has no swimmers.
Now you can fuck without condom. Enjoy.
It's not the same as the image (it was a Reddit print I saved long ago), but yes, it's on Amazon
take this! It may help you on your quest
male chastity cage https://www.amazon.com/Ineardi-Male-Chastity-Belt-Cage/dp/B00BPN2C4I