We think you are being a bit hard on the OP. We also recognize that you are a man in the lifestyle for many years. However, he was just stating a question, and maybe his English is not to Vegas standards.
He mentioned that they had some experience, and that it did not turn out so well. You could have counseled him to support his wife and let her know that the failure may not have been her failure. However, she is placing blame on herself and possibly not allowing herself to open up.
If after saying this, she and he could have said that swinging is not for them. We think you are not being very sensitive to them.