My advice is do not get involved with OM at all. I don't know how you plan on showing him she enjoys your company but if you get tangled up with him your emotions will kick in and it will get ugly. At some point you have to stop her cake eating.
Right now SM you need to slow things down. To me you seem to be all over the place with your thoughts. This isn't a sprint it's a marathon. I noticed that you said what work your W would need to do if you R but you didn't mention what work you would need to do. So what work would you need SM if you R?
M 44 W 43 S 23 S 15 INILWY 9/11 Divorce Mediation started 3/13 June 30 the day W is moving out