Having arrived here from a similar circumstance and knowing the history I'm confused why his comment has struck such a nerve.
Well known fact he never wanted this.
Well know fact he's tolerating this.
He's the frog thrown in warm water and gradually turned up the heat...he's pushed back on his limits, house visits, last dance on New Years eve, PIV, etc, when the water gets too hot or starts to boil he pushes back .... all in the mindset of tolerating.
Tolerating is the key word. NOT HAPPY ....NOT COMPERSION
It could be that within the "tolerating" frame work to him it's simple pain management. What's more painful more uncomfortable...whats less painful or less emasculating. Agreeing to this or offering that.
The downside to counseling is hearing things that might hurt your feeling. And people start feeling they can share thoughts and feeling.
If he's telling the truth ...I see him saying the pain and work of you being sick was well worth the pain and discomfort that he might feel in the unknown weekend date's. A calculation on what he knew from history and what he thought he could handle....and the assessment of the fragility of your health.
All of his thinking might have been crazy but not necessarily dishonest. And what difference does it make what reasons are used to tolerate his marriage. The kids, splitting 1/2 your combined assets, love ...or not having to see his spouse so sick .... or not having to be nurse Betty . A reason is a reason. His reasons. People feel pressure to do things all the time that they regret after the fact that doesn't make them dishonest.
As I said going through this myself I would agree the feeling of betrayal was the number one problem for me. I'm not sure that goes away in a tolerating mindset.
here where I see this headed if you stay together for the kids ... http://www.polyamory.com/forum/showthread.php?t=18760