I used to take my wife to the edge with my mouth and, knowing where she was by her breathing, etc., I'd throttle back for a while, then take her back to the edge, then slow down. She'd complain (sort of) at first, but she loved it when I finally let her come. She would shake and twist.

I think orgasm denial works best in that situation, when either one or both partners are familiar with the other's thresholds. I wouldn't expect a provider to know where my line was until several meetings, and I wouldn't know hers for a while either.

I'd say keep trying with your wife and if that doesn't work, with your ATF, if you have one.