I really am so sorry that you're caught up in all of this, and to be pinioned by the addiction of another is always an ugly thing.
Others have given similar advice to mine: I think you have to get to the point where you simply tell your spouse, "I know this is what makes you happy, but I can't do this anymore. I am setting a healthy boundary for us, because I love you/us. I won't give my permission/say yes to this anymore because I love you/us.
Your spouse has got to know that you're firm and ready to do the LRT. Besides, how healthy is it for you to have him off with someone else--what risk are you putting yourself at?
