She has genital herpes, which she didn't tell him about until after they had messed around. He, and I, made the decision that was something we did not want to risk, especially because they had dated for months and she had never told him. But he still valued his friendship with hHer, just did not want to proceed with a sexual relationship.
It would be nice if we could avoid getting bogged down in discussion of whether my husband should have slept with her or not. He was very relieved at the time that they hadn't had intercourse yet, and relieved when he retested and was fine. And sleeping with her hadn't been a big priority for him at the time anyway, since he already had multiple relationships.