She said all of this happened because she didn’t feel like I was showing her attention
Ugh. So, not only has she cheated for the better part of a year and created a situation in which you had to DNA your new baby, she's going to stand there and insult you to your face by BLAME-SHIFTING her choice to cheat onto you. Wow.
What happens next time she feels like she's not the center of your attention, hmm?
I'd like to say I'm surprised by the lack of critical thinking which goes into a response like that, but really I'm not. It's par for the course and it's utter bullshit. NONE of this is your fault. Cheating is 100% about the cheater. You were in the same marriage she was, and you didn't cheat. It's about CHARACTER. It's about the gap between a WS's stated values and their actual deeds. Your WW has a "but..." in her core value of fidelity. ie. "She believes in fidelity, but... not if she's unhappy or whatever." You see how that works, right? You and I don't have a "but..." in our core value of fidelity. We have a "so...". ie. "We believe in fidelity, so... we don't put ourselves in risky situations with people of the opposite sex." This is the BOUNDARY. We build these boundaries around our core beliefs in order to protect them. It's intuitive. We don't sit around thinking about it. But it gets done.
For cheaters, not so much. Their core values are weak and permeable. They haven't spent too much time thinking about what they truly believe in and what value they place on those beliefs. I can't be made to cheat with a gun to my head. My core values are strong. My boundaries surrounding them are tall and inflexible. You see how that works? It wasn't your fault. The failure is with your WW and in how she interacts with her own values/belief system. You didn't cause that. You couldn't have fixed it. And you couldn't have stopped it.
I know the most succinct advice is to file for divorce and put the cheater out of your life... and it might come to that, it really might. But for right now, you're not at any obligation to make a quick decision. It sounds like the affair has been stopped, although you and the OBS would be wise to continue monitoring. Broken NC is common in the early days and you're dealing with a proven LIAR. There's no pressing reason though why you can't make your decisions on YOUR time table. I certainly wouldn't start MC with her. The last thing you need is some quack trying to find common ground on who's to blame. Cheating is 100% about the cheater. It's about character and about how a person relates to their own core values.
I'm going to save myself some typing and reprint something to warn you off of therapists who go in for the blame shift of the "unmet needs" model. It's kind of long, but I think it will help you see what it is that your WW needs to accomplish in order to become a worthy candidate for R. It's not just about forgiveness, you know. It's about whether the cheater can CHANGE.
My own WH went on a Craigslist binge six years ago, multiple partners, various degrees of emotional attachment. He even thought he was in love at one point. But ten years before that, I'd caught him out in some online shenanigans, porn, cybersexing, emotional affair, etc. In fact, I caught him out only two weeks before a planned meet-up. I'd already seen an attorney before I confronted him and I was bent on divorce, but he pretty much cried his way out of it and I settled on MC. As you might have guessed already, we too were bamboozled with the "unmet needs" model of therapy, which sounds so reasonable. I upped my wife game, and did my best pick-me polka, but within a couple of years, he was right back at it behind my back. By the time we reached the ten year mark, he had screwed up his nerve to go live and in person on Craigslist.
Of course, I was pretty shocked as you might imagine. I thought we were good. I thought his "needs" were met. Damned if I hadn't been turning myself inside out for a decade to make sure, right? The more I thought about it, the more I revisited what I knew about the "unmet needs model", the less it made sense. I was doing everything right and he still CHOSE to cheat.
Here's the fly in the "unmet needs" ointment...
Healthy ADULTS don't need to be validated. They validate internally. Healthy adults are self-fruitful in the matter of contentment and life satisfaction, and when things come up which make them unhappy, they address the cause and solve the problem. OTOH, the vast majority of cheaters cheat because they're seeking external validation. They are NOT emotionally healthy. They can't do it on their own. They've got a hole inside them and no amount of external validation will fill it. Certainly, the old and familiar validation of a spouse doesn't get the job done. Our "kibbles" are stale and boring. They don't create enough adrenaline anymore to make the cheater feel special. It's like getting an "atta boy" from your mom, right?
This is old pop-psy which is still being taught in schools and still selling books. But it's bullshit. NOTHING you can do (or fail to do) can MAKE another person throw away their core values and do something that's in this kind of opposition to good character. If you're a person who BELIEVES in fidelity, who VALUES fidelity, you don't cheat. End of story. Because when we truly value something we protect it. The cheater has a "but..." in his values system. ie. "I believe in fidelity, but... not if my needs aren't being met." For people like you and me, we have a "so..." in our values system. ie. "I believe in fidelity, so... I don't put myself in risky situations with the opposite sex." This is the BOUNDARY we create organically. We don't sit around planning it out. It just happens, because it's innate to our character to protect what we value. The cheater doesn't have those boundaries because he doesn't really honor his values. He only claims to.
I'm not saying that your marriage is over or that your WH can't change. What I am saying though is that this "unmet needs" model is NOT going to challenge him to clean up his flawed character. In fact, it allows him to offload responsibility onto the marriage and onto YOU. It's not your job to MAKE him feel (fill-in-the-blank-here). It never was. It's his job to control his feelings. You could have been doing everything exactly perfect for the entire length of your marriage, and he would still have cheated... because there's NOTHING in his character stopping him and he has no coping mechanism to fall back on when he feels unvalidated, inadequate, unappreciated, etc.
It's HIS job to see that his "needs" get met. Sometimes that might mean negotiating with you, say if it's about sex or about the division of labor in your home, etc. But sometimes, it might mean that what he sees as a "need" is unhealthy in an adult, like external validation through attention and flattery.
MC's are there to treat the marriage. The marriage is the client. So, of course they're going to talk about communications, resentments and expectations. The MC doesn't want to alienate anyone, so s/he's looking to find balance on both sides. But marriages don't cheat. People do. The only way your WH is going to make a change that safeguards against further perfidy is by correcting his need for external validation and becoming an emotionally healthy adult whose deeds are as good as his word. No excuses, just honoring the things he claims to value. For that, I would recommend IC (individual counseling) with a therapist who is well-versed in adultery.
The last thing any newly-minted BS needs is to walk into an MC's office, believing that they've come to safe harbor, and being handed a copy of The Five Love Languages or some other "unmet needs" gobbledygook. It would be really nice if we actually did have the power to control our mate by giving them "acts of service" or "words of affirmation", but sadly, we aren't gods who can stop a cheater from seeking out his/her choice of adrenaline rush and new kibbles. Although, this kind of pop-psy suggests that their behavior is somehow our responsibility. The more you dig into this ridiculous line of thought, the more absurd it becomes.
Anyway, my advice is to take whatever time you need to make sure that you're making the best decision for YOU. What your WW wants is immaterial. She's had her choices. Now, it's your turn to make yours. Don't pressure yourself and don't allow her to pressure you. It's okay to not know what you want right now. You've been betrayed and traumatized. It's going to take some time to sort through your feelings.