Bacterial vaginosis

Everytime my husband ejaculates inside me a few days later I get slight cramping and then I get a yellowish green smelly discharge. It smells horrible. I take antibiotics to get rid of it. It's starting to take a toll on our sex life especially since we'd like to have another child. He's been checked no STD's I don't know what to do. How can I stop this so we can move forward to have a shot at conceiving?