At the end of the day, gathering the doggies and going somewhere else with only mentioning that you need time to yourself isn’t a huge deal.
Step by step. You probably recognize that time to be out of a situation gives you a better viewpoint. I’d not tell him that.
When he is gone and you’ve made your arrangements go. You don’t have to say how long or anything. He doesn’t deserve your explanation.
I disagree you should over trying contact the other woman. It’s a type of behavior that will only bolster his value in her eyes and to be frank your motivation wouldn’t be to save her, but to hurt him.. don’t do it.
I have been massively cheated on so I say this with love. I’ll send support however you need it. Just like everyone here.
But if he’s allowed and justified the freedom to text and do as he pleases, you are justified the right to go to a hotel, parents, friends, and away to do some thinking.
Lastly, sorry to be cruel but I feel it should be said…. You might not have been the first to be given that poem that meant so much… he seems to have his go to pattern. It is not yours as a couple if it is not shared with you both. Much like the fidelity and committed it was meant to represent.
Just pack up however is good for you and leave without warning. O goodbye no nothing. You need to feel your power as an individual. There is literally nothing to lose.