Okay, not ideal, but with enough love and attention your S will be fine. Just don't argue in front of him and spend lots of daddy time with him. Sideline your feelings about this but as your W will happily spend time with OM rather than her own S, let her. That way you can do fun things and protect him.
To win in this keep detaching. If she is happy, so what, sad so what, kind, so what.....don't be fooled into thinking you are making her feel anything or causing anything in her. She is making her own foolish choices just stay clear and focus on your S.
You are doing great. Keep up the fitness etc. Keep a level head.
Keep going chap!
Surfer.
M46/W40/D8/S6/T20/M12/Separated 6/2016,W takes kids Issues2009 Wpartying w/g.f's2013on EA2013PAdeniedWleavesMBR ImeetAP/EAhalts VariousBDDates MFCourse WSpew EAresumes I halt Wrages DBIng4/2016