My (40's m) wife (30's f) cheated after 14 years, while drunk/high but wants to fix things.

I'll try to keep this short as possible and I doubt anyone will even read this, but maybe just putting it into words will help me.
My wife was my best friend. The majority of the last 14 years has been wonderful. I loved her more then anything, and she loved me too. She is a great person, with a bit of a temper, but she was the ying to my yang. I am a very even tempered person, and I try my hardest to stop and think before I act, while she is a bit more carefree and emotional. But, it was a good mix. She was the other part of me that I was missing, and I to her.
We had been a happy childfree couple for many years. She had always told me that she did not want children. I had a daughter many years before we met, and she helped take care of her when she visited. She was a great second mother to her. Like any couple, we had our ups and downs. There was some issues with her getting too close to a co-worker years ago. She lied about the problem initially, but eventually we worked past it, and I thought we were stronger then ever.
We went out together a lot. We drank a little more then we should have for our health, but I didn't see it as a "drinking problem" for either of us. We both worked in hospitality, and it kind of goes with the industry.
Then she changed her mind about having a baby. Maybe it was that she turned 30 and "baby fever" kicked in, or maybe it was seeing her sisters so happy with little ones that changed her mind. It doesn't really matter. But, we had the conversation one night, and i told her that I would love to start a family with her. However, the timing was bad. The short version is that both of our jobs were possibly about to end, and we didn't know exactly what was going to happen in our near future.
We eventually got back on our feet, after what turned into a devastating year for us where we lost everything and had to start over. During the bad times she started drinking more and more. She has a family history of alcoholism. Things got pretty bad for while with her behavior because of drinking and depression from us having to start all over. But, as I said, we pulled out of it, we got back on our feet and started putting our lives back together.
However, her drinking continued to be a problem. She would get drunk and mean and call me names. She got drunk at work and was fired for drinking on the clock. She was still my wife, and i still loved her so I tried to support her and help her. She would quit drinking heavily for awhile, and then a few month later go right back to it. She was always sorry when she was sober, and most times were still good, but once a month or so she would get wasted and tell me she hates me and that she is leaving me for a "real man that will have a family with her". I tried to tell her that we can't have a family while your drinking and acting this way.
A few months ago, things started to really go down hill. She started drinking everyday, including hiding alcohol and lying to me about her drinking. She also started doing cocaine on an almost daily basis. I don't judge drug use, we had done it together plenty of times in the past, but not often. She was lying to me about her drug usage. I confronted her several times, I reminded her that she told me she wanted to start a family, but was not acting in a way that could ever have that happen.
Then it happened. She was hanging out with a guy that I thought was a friend, but it turns out he was not. She was drunk, they were doing coke together. He and I had previously had a few discussions about our problems, and he used that information to say all the things she wanted to hear. He manipulated her into getting laid. Yes, she still did it, and it was still her decision, she was not r***d. But he did prey on a drunk wowen, gave her cocaine, and when he got laid, kicked her out of the house. I had to pick her up that night. She gave me a story about them going to get more coke from his house and he started throwning up and then she just wanted to get out of there.
If she would have be came to me immediately after that happened and confessed, and was willing to change, I think I could forgive her on the spot. Get her help and try to move on. However, that didn't happen. I found the text messages they sent each other about a week later. I confronted her, she told me what happened, and she agreed to leave and go back to her parents house. That where she is currently.
When I found the messages I didn't know that she was as ****ed up as she was that night. I also didn't know how much he had manipulated her to get laid. I have since found out the he has done this before, and this is his MO for getting laid. He is a horrible person that waits and preys on girls that are vulnerable. That is just gross.
She is incredibly sorry. She knows that what she did was wrong, and she admits that what happened that night was her fault, even if he said all the right things. She wants to try to work this out and try to save our marriage. She is has already quit drinking, and says she will never drink again. She says that she was angry that we didn't have a family, but knows that the reason we didn't was because of her. She has said that this was the rock bottom she needed to hit to fix herself and to be the person she used to be.
I don't know how to move forward. She was my best friend. She was the love of my life. I know that without the drugs and alcohol none of this would have ever happened. But, how do I ever trust her again. And even if I can eventually trust her again, the basic problem that we had was starting a family and I don't think I can trust her enough in the time we have left to start one. Her biological clock is ticking. I want nothing more then to have back what we had before our lives were destroyed, but nothing can turn back time. Nothing can undo what has happened. I realize that I wasn't perfect either, no one is. But, am I just prolonging more hurt in the future? What do I do?
TL:DR Wife started drinking and doing drugs and cheated on me. She swears she is done with drinking and wants to come back and start a family together.


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