This might be something:
I think the control issue came up because my husband made it very clear to his friend that I was not at all OK with her failure to disclose her STD status and would have done everything in my power to halt them being sexual together in the unlikely event that he decided the risk was worth it.
HOW did he express that? Jsut like that? Because
"My wife is not at all OK with your failure to disclose your STD status. She would have done everything in her power to halt us being sexual together in the unlikely event that I decide the risk was worth it."
is a different thing than
"I am not comfortable with you not disclosing your STD status up front to me. As a result, I am not comfortable sharing sex with you at this time."
The first way could trigger defensiveness toward you upon first hearing it and it's a lot of words before he finally "appears" in the sentence. Not til the end. Where it is "until I decide the risk is worth it."
But the risk of WHAT? Sharing sex? Or risk of invoking the wife's wrath?
That sort of phrasing heard by a person who is cranked up? Is unclear and could lead to deciding the wife is "controlling.
Whereas the second phrasing of it? He's present the whole time in that sentence. You don't even appear in it. He very well may have agreements to meet with you, but he's not dragging that into the sentences, is he? It expresses his feelings more directly too.
You guys could examine HOW he expresses himself. See if that is or isn't another area he could improve.