Ed you say there is nothing you can do about another man being in your M. IMHO what I would do is tell her you do not appreciate her lying to your S and to you. I don't think your S should be exposed to her lies and addiction. It seems that you have been her doormat for a long time. She has no respect for you or your S. If it were me I'd stop being her doormat and give her a dose of tough love. I don't believe she will snap out if this until you stand up and tell her enough is enough.
M 44 W 43 S 23 S 15 INILWY 9/11 Divorce Mediation started 3/13 June 30 the day W is moving out