I know what you mean about sidestepping the issue. However, given that the need which an affair fulfills for most men is how good it makes them feel about themselves, and given that they tend to "rescue" damaged women, it is EXTREMELY difficult for them to hear that they need to crush those women further with honesty. It would make them feel bad about themselves as men who like to help.
I was certainly frustrated by the way my H refused to see the negative things about his OW at the time they ended their relationship. I think that over time he was able to admit their existence to himself somewhat more--after all, he had painted an unrealistic fantasy picture of her in his mind. But, the closer he drew to me, the less it mattered, since his focus was now on me.
I do think that although it feels "fair" that your H should tell his understanding of the truth to the OW, it would be better not to insist upon it. Your H will only feel that you are bullying him to do something he really hates to do (which probably brings mother-baggage into the situation). Plus, the OW would only think, "She made him say that," rather than accepting it.
Try not to think of your H's behaviour as avoidant, cowardly, non-confrontational, etc. Are there positive sides to such behaviour? Could you re-label them in a loving, accepting way? None of us are perfect, so it helps our relationships to accept and understand the flaws of others.
