There isn't enough information from the OP to determine whether the wife is upset enough to want out of the marriage, or which of them, if either, is being wronged here.
Who asked you to decide who is being wronged here? Not me. I just asked for a bit of support and wisdom to help me though this tough time.
First, we were told that the wife has recently wanted to go out with friends, plural, several nights per week and was going on vacation with one of them. This appeared to lead to a little speculation that she was having an affair.
No. I wrote that "She goes out with her friend(s) 3-4 nights a week and she is going on vacation with them at the end of the month". The speculation about the affair was not mine.
Then, in post #103, it was revealed that the main problem is one female friend who came into the wife's life 6 months ago. This still led to speculation that an affair still might be in play, either between the wife and GF, or the GF is going to introduce some new man to the wife and, that's all she wrote folks!
No, I did not say that the GF was the main problem. I just said that she is making things worse. Again, the affair speculation was not mine at all.
In post #105, the new GF is criticized by OP for spending some time away from a permanently disabled teenager who requires constant supervision. We're told GF's husband doesn't like being "stuck at home" taking care of his own kid.
You got that wrong. The husband is the one stuck at home all day long to take care of the kid while she works (he gave up his career to become a stay-at-home dad). What he does not like is that now he is also stuck at home in the evenings and on the weekends too when his wife goes out and parties. I personally think that he has it rougher than me.
There's more contradictory information. Let's not forget that OP said in post #103 that the GF isn't responsible for all of their issues. That suggests to me that the claim of everything being just fine for the past 17 years isn't exactly accurate.
I said that we had a "pretty solid marriage". But it was certainly not perfect (Do you know a perfect marriage? I don't). We have had some disagreements over the years but nothing that I regarded as an existential threat to our marriage or even a rough patch.
Is OP's wife letting someone she just met 6 months ago break up what was a perfectly fine marriage, as OP feels is happening? Why is the wife so susceptible to this GF's influence?
That I don't know and I would love to know the answer to that last question.
Is the GF a horrible wife and mother for wanting some time away from a teenager that would be more stressful to care for than your average teenager? Does she work and leave the kid's care to others most of the time anyway? Then it could appear as though she takes little to no responsibility for the kid, thus leaving her husband "stuck". Or is she a SAHM who takes primary care of him most of the time, all day, every day, and is desperate for some time away a few evenings a week, which her husband appears to begrudge her?
I answered above. But honestly I am not all that interested in the GF's marriage dynamics. I'd rather focus on mine. And I never said that she was a horrible wife or mother.
The truth is, we don't know. OP hasn't exactly been forthcoming with pertinent details, leaving out a relevant fact until post #103. I'm pretty sure there are other relevant facts that aren't being disclosed and perhaps they shouldn't be.
You are right about one thing, you don't know. And I don't owe you details, facts, or anything else. You are not the arbitror of truth.
I'm not taking sides here. OP's wife could have changed radically in habits and personality strictly because of her newfound GF, who has been badmouthing the OP, for what and why, we don't know. If she's that easily led astray, that doesn't speak well of her and maybe OP would be better off without her.
Well it sure feels like your mind is made up for someone who does not know much about the situation. The way you repeatedly twisted my posts betrays your own bias.
OP could be jealous/possessive/insecure and not want his wife to have a relationship that he's not intimately involved in. This could be coming across to the GF, either directly or indirectly, leading to the GF badmouthing him because of it.
I have met the GF twice (only briefly) and we did not speak much. She does not know anything about me - except what my wife tells her I suppose.
What is the truth? We simply don't know, because we're only hearing one side of the story.
What do you expect? Do you think that my wife is going to log in and give you her version of the facts to perfect strangers? I am not here to seek couple therapy. I came here to vent, with the hope that I would get some moral support and wisdom - which I did receive
To the OP, speaking as a happily married woman for 26 years, everyone has disagreements. You're a couple, but you're still individuals. Compromise is key.
Well, thanks for that advice.