There are no ways to get around the trust issues as I see them other than reassurance and time. My W did something very minor and I still find myself checking up on her even when I know she isn't up to something.
That being said, if I was in your shoes I might try to turn the committment issue around on him. If he questions your committment to him I would consider something like this:
"Hey pal, committment is a two way street. You cannot expect me to remain fully committed to this R while you obviously are not committed to repairing it and achieving some semblance of a normal healthy married R. I love you, H, but until we both decide to work on building the future rather than meting out punishment for the past I cannot remain fully committed to the R indefinitely."
Like I said, I'm not exactly a paragon of marital success myself so I have no idea what will or will not work for you. I'm just throwing out ideas.
Gone the carvings and those who left their mark. Gone the kings and queens, now only the rats hold sway.
