Should I Tell Her To Move Back.....?

[gr8 day 2B alive]

how destructive this GF has been to his marriage to comment on it,

Ever since w started hanging out with GF, whom she reunited with from FB, the GF has been introducing OM into W's life. In fact GF pressured her to be with OM.

I feel I need to treat this GF as an OM in my relationship with W.

Would we not expect our spouses to eliminate all contact with OM if they were in an affair?

I am treating her GF as the threat to my M.

If am wrong on this please enlighten me. My ears are opened.