It's been a while so I'm not sure if you'll see this or not, but here are some things to consider:

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I felt secure about or marriage though she had three affairs in the past and "broke up with me" she never filed divorce and after i discovered the affairs she came back to me and we worked it out. I never thought she would leave me again after the last affair about 2 years ago. We were still sort of recovering from that and I was dumb thinking once we moved and started over things would be good so i was chillin'.

She's got a track record here so it's going to take some radical changes if you want to save this, and chillin' is probably off the table. Are you down for living a different life where you both are radically honest with each other and take steps to make keeping secrets from each other impossible? That's what you need.

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I got into playing an online game and kind of upset her by being really into it a lot of my time. She complained about it but never gave me an ultimatum or anything, seemed to tolerate it. Then she started going out at night to play board games at her sisters house with her friends. More and more she was over there.

From personal experience and talking to dozens of guys in this situation over the years...you might not have been paying enough attention to catch the ultimatum. Or...she might have figured there was no point in giving one. This is a big deal here, no relationship you get into will work until you fix this. She shouldn't have to give you an ultimatum. If she complains about something and you keep doing it, you are non-verbally telling her that you don't care if it bothers her and her suffering doesn't mean anything to you. The point of a complaint is to say "hey, this is hurting me". The good news might be that you can really show her you are a new man if you do something like quit video games. It sounds like you are addicted....many guys our age are. Take that time, and find a way to spend it with her, regularly. When you are 80 you won't regret missing a game from the 2020s but you will never get these prime years back with your wife. You take that time and invest it in her and your marriage and it becomes worth something, time you didn't waste. That's all OM did to win her over, more than likely. Put time you spent on video games into spending time with your wife. Easy fix for you if you can earn the opportunity with her again. And if you don't, a valuable lesson for you if you find someone else. Look up POJA here. Stuff like playing games when your wife is complaining about you playing games is going to doom any relationship.

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up until today ive kept quiet mainly about what went on to anyone besides my friends, I dont put anything on Facebook or talk to her family about how hurt, sad etc I am. I have messaged her back and forth about things im going through, shes told me a few times she wasn't sure about her choice anymore and gave me little false hopes. About two weeks ago I got tired of the "im not sure" and issued an ultimatum, she didnt come back, she said she cant hurt him because he is super nice to her, has never hurt her and is taking care of everything and she doesn't want to mess his kids up either. Ive told her that she is killing our kids, they are confused about why she lives with a friend and why we are separated now. I have been messaging her almost daily about things for the kids, kind of in a nice way trying to show her that its killing them, that she is doing the wrong thing, that she deserves better and that she is being manipulated and used to be this guy's new house wife.

Expose to everyone recommended in the exposure threads on here. If you don't, OM and your wife will tell everyone that your marriage just fell apart on its own and not as a result of any affair, and your kids will learn the lesson that if someone cheats on them, they should just take it like a doormat. If your daughter was cheated on, would you want her to stay with a man that insisted she kept it a secret? Of course not. Expose the affair.

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all for this man she initially had no sexual attraction to who isn't her type and is maybe a 5 on the scale of good looking she is a 10

Like you said....this doesn't matter. Modern guys spend all this time worrying about stuff like this that doesn't matter. What does matter is he probably doesn't play video games late into the night when she's already told him she doesn't like it.

It's been 6 months and so maybe this has progressed in the legal proceedings and maybe it hasn't.....but you need 2 things.

1. Exposure - You HAVE to put a cost on them continuing this that makes it a painful commitment for them to keep up. They need to know that they will pull the wool over nobody's eyes that is close to them, everyone will know they sacrificed two families and all of these children for their own selfish impulses. You have to make that stick to this, nobody else will do it for you.

2. Plan A - You need to run a HARD Plan A. Get in the gym, work on your career, make a "spoil her rotten" list, and ditch the gaming. Every time she sees a gaming console or whatever you use, she is going to think about how you picked it over her. If the divorce isn't finalized, then nothing is settled and there's no rules saying he belongs to her. Don't avoid him, he's a piece of trash and he needs to know he stepped into your lane and you are here to push him out. If he wants to show up at family events or whatever you need to be there looking well dressed and making passes at your wife right in front of him like he doesn't exist. Who cares how it makes other people feel, he's the person out of place and it will probably give your family/friends some backbone to tell him off anyways. Your kids want you to fight for her like it's the only thing in the world. You know that, right?

PS - Talk to your lawyer to make sure custody and property schedule aren't settled if possible. Don't make this easy on them, there's no bonus points for being a nice guy when someone is destroying your family.