*hugs* Good luck with counseling and growing with your wife in whatever directions that takes you both. Sounds like you're both burnt out with jobs and kids.
There is a lot of talk about "hate" in your posts. She hates you for your job. You hate your job. She'll hate you if you tell her to break it off with T.
Perhaps you could find a job that leaves you closer to home... Be around to spend more time with the family, more time connecting with your wife.
No marriage is perfect. No couple is entirely stable, including primary poly couples. Her falling for T is clearly showing you there is something missing for her in her life that she'd probably rather you'd provide.
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve. -- Shelley
me: Mags, 59, living with:
miss pixi, 37