At first, I was thinking that your sitch was a lot like mine in the beginning, but it moved so fast after that.
One thing you need to decide is do you really want to save your M. When I read about your L wanting you to file right away, it made me think of just why there are so many D's in the USA - The L's for sure want to have their income! But is it really what you want?
For me, if your H wants to leave, he should file. Then the burden of ruining the family is really on him. Even in the midst of all of what you described, I could sense that your H is still struggling with the idea of leaving his family, that is why he was not the one to bring up separation. But sometimes, we LBS feel that the WAS act nastily to us to spur us to ask for a separation, so that they can point the blame on to us all the more. Sad to say, many fall for this, and in the end, the LBS is actually the one who determines the fate of an M.
Of course when a person is in the throes of an affair, they won't have any feelings for spouse! But will those "chemically induced" in love feeling last? Most articles say that they fizzle out from between 6 mos to 2 years!
My H was so much like yours, but I just hang in there. Many people told me to make him choose, S, etc. but I felt that he was in a fog and any decisions he would make would be influenced by his state of mind. I also thought about my D a lot and did not want to subject her to a broken family. My H actually did initially bring up a D, but never acted on it, and we are still together now more than 1 year after the bomb. He now admits that his feelings for OW are waning, and I just am hoping and praying that it will be completely gone one day. You know, no matter what you do, you cannot force another person to love you.
Work on yourself, RSGG. Since you are Catholic, check out the concept of "standing' for your M. I read a lot of material from Rejoice Ministries, and they send daily devotionals which are very inspirational and helps me to hang on to my M.
Detachment is indeed very important, and it is hard to learn but is the greates lifesaver in this situation.
You take care and God bless!
Me:49 H:45 D:12 M:14 T:18 Bomb: 6/26/10 EA: 9/3/10, fizzled out slowly, now ??? 11/5/11 Retrouvaille Finally piecing.... Its peaceful at last, but we got a looong way to go