Setting Boundaries for MLC Alien H

[In Limbo]

I have done very well today and tonight, not bringing up R, not asking questions about where H will be tonight and certainly nothing about OW. Was pretty cheerful all day and H seemed to respond positively. BUT he still went out tonight, ditching his own friends. At the risk of getting thrown off this forum, I have a question that I hope experienced DBers (especially with MLC) will respond to.

Ok - don't freak out, please read through before responding....
I'm wondering if it is ever the right thing to do to contact the OW spouse in the case of EA. Here's my logic. OW's emails prior to 3/11 indicated she loved her H, was more interested in friendship but didn't want to hurt my H's feelings and I got the impression she doesn't know how to have boundaries or cut someone off when they cross the friendship line. My H is the type man that once he decides what he wants, he pursues it vigilantly and usually gets what he wants. Since then I do not see his emails/texts, but I know they have continued to be in contact, have attended a movie/party with a friend of hers, attended a concert, believe they have met for lunch, etc. His pursuing seems to be having an effect. I'm thinking that her spouse is sitting where I was in the past, fat, dumb and happy and has no idea that my H is actively pursuing her for something other than friendship. If I were to tell him (assuming he loves her and wants to remain married) the facts as I know them, he could possibly reconnect with her and encourage her to discontinue contact with my H. I do realize there are risks - he could leave her (doubtful since it's EA, not PA and H has been primary pursuer) or he could tell her about my contact, she tells H and he gets furious (ultimate snooping). I realize that even if OW stopped contact with H, that would not solve my problems or end H's MLC. I guess this is a combination of me not wanting to see OW's H lose his W like I'm losing my H and (if I'm honest) me trying to reduce the distraction OW is having on H (ok, yes, that's controlling). I don't want to get 6 months down the road and think that if only OW's H had known earlier, he might have rescued his M.

So, please don't kick me off, just help me understand the why's and why not's of doing something like this.