How is this allowed?

OK so my soon to by ex-wife 33F and I 35M have been married for 12 years. The marriage was great up until about 3 years ago. I was at work one day and a random number texted me stating that my wife was having an affair with our 8 year old son’s pediatrician. When I confronted her about it she admitted to texting him but said nothing physical ever happened, when I asked how long this had been going on she said 8 months. Now, obviously I didn’t believe her at that point, what guy sticks around for 8 months just to text, oh and this Dr was already married with three kids of his own. But, against my better judgement I believed her when she said it was only texting, I think a part of me just didn’t want to accept it as well. For the next 2 years everything seemed fine, up until about a year ago. She works at a hospital and out of nowhere told me that she decided to switch to the overnight shift. I work during the day so I said this would mean we would never see each other. She assured me it was only going to be a couple nights a week and we would still see each other plenty. Over the course of the year I began to see her less and less to the point that we would go days without seeing each other. I’ve always been the more attentive parent when I comes to school and soccer for our son so it wasn’t unusual that I was the one going over homework at night, reading books before bed, and taking him to and from all of his practices and games (One team he plays for is located an hour away from our house and had something going on 3 days a week). I enjoy cooking so I’ve always been the one to cook dinner, and of course I had my usual set of chores to do around the house like mowing the lawn, taking care of the pool, snow blowing and shoveling in the winter, plus i’d help clean up any messes around the house. Since she worked at night I was also the one that got our son up and ready for school in the morning. However, I began to notice she was never home during the day either, so the chores she took care of never got done like the laundry, dishes, vacuuming, and mopping. Now, me trying to be a good husband, started doing all of those chores as well on top of everything else. I have a pretty good job making over 6 figures a year, and on our tax return it showed she makes around $35,000 last year, so naturally I paid for everything. The only bill she was responsible for was her cell phone which was just over $100 a month, so you would think since she only has the one bill she would have quite a bit of money saved up. One day (of the few that I actually saw her) she asked if I could co-sign a loan for her, and when I asked for what she informed me she was $19,000 in credit card debt. I was shocked when I heard this, i thought how could she be in so much debt when everything she has is paid for by me. I told her no I wouldn’t co-sign, I thought it was unfair that I was paying all the bills, was the only one contributing to any of our savings and she was just spending away every penny she had plus a bunch she didn’t have. I offered to help her budget her money because she made more than enough to cover her cell phone plus save and have some spending money but she refused saying she had a plan and wanted to do it her way. Recently, we went on a trip to Disney with my family and for the entire trip she kept making excuses to leave the park and go back to the resort on her own. I was upset by this, I told her we hardly see each other as it is and I was hoping this trip would allow us to spend time together. It didn’t matter the excuses kept coming so I spent most of the trip with my son, which to be honest I enjoyed spending the time with him and by this point we were both used to mommy not being around. The night we get back as soon as we step in the door she takes a shower then says she has to go into work, at this point I was done, I didn’t want our marriage to end but it was clear she didn’t want to be with me anymore. Now I’m not saying I was the perfect husband but I thought I was good to her I treated her well, helped out when she needed it, and provided a nice life for her financially. On her way to “work” this evening she happened to pass my brother who was leaving my parents house. Now my family is very close so when my brother saw her he called my mother and asked where my wife was going and my mother told him work. When my brother heard this he knew it wasn’t true because when he saw my wife she was wearing a baseball hat and she wouldn’t be wearing one if she was going to work. My mother, wondering what my wife was up to, decided to go over to the hospital to visit but when she got there and asked she was told my wife wasn’t scheduled to work that evening. My mother tried calling her for hours and when she did finally pick up she told my mother she called out because she needed a break. Since my mother was already at the hospital she knew this was a lie and that my wife wasn’t even scheduled to work that evening. When my mother called her out my wife admitted that she was actually driving around with her aunt about an hour from our house, my mother then told her to turn the car around and get home to her family, my wife said ok but she never came home. I had no idea any of this was going on until the next morning, I saw my brother and he asked if I had talked to mom and when I said no he told me everything that happened the previous night. After hearing this I called my wife and we met at our house, we talked for a bit and agreed to get a divorce, the marriage just wasn’t working anymore. My wife voluntarily left the house leaving me and my son to live there, but to be honest it didn’t feel much different since she was hardly home anyway. After a couple days I got a message from someone on facebook telling me that for the last 3 years my wife was having multiple affairs three of them with Dr’s she worked with at the hospital and one of the with a convicted felon that is currently on parole. The girl from facebook gave me so much detail about everything there was no way she could have lied about any of it. I saw me wife the next day when we were exchanging our son and I confronted her about it, at first she denied it but then after I started giving her more and more details she finally admitted it to be true. I of course was devastated, i was willing to accept she just didn’t want to be with me anymore but finding out she was sleeping with four different people behind my back crushed me. When we first agreed to get a divorce she told me all she wanted was her car, that i paid for, and her credit card debts paid. I didn’t want to do any of it but I figured it was worth it just to get it done as quick as possible. Of course that’s not how it ended up playing out, as soon as she talked to a lawyer her demands changed immensely. So to summarize, my wife of 12 years has been cheating on me for at least 3 years that I know of basically abandoned me and her son for the past year accumulated $19,000 in credit card debt while pretty much everything else in her life was being paid for by me and now wants to take half of everything I saved up which would picket her about $200,000, a quarter of the value of the house (my parents co-signed when we bought it so there’s 4 people on the deed) so that’s another $100,000 plus she wants to split our son 50/50 even though she went days without speaking to him before the divorce and in NY child support is given to the parent that makes the least amount of money on a 50/50 split so she would get %17 of the combined household income per month. How is it possible for someone to cheat for years contribute nothing financially and take no responsibility for raising their son and still be able to come away with all that? I’m going to fight for primary custody because I dont think shes a responsible parent but she does love our son and she is nice to him when she actually sees him. But as far as all the money it would probably cost me more in attorneys fees to fight it than it’s worth so I’ll probably just let her have what she’s “entitled” to. Any suggestions on what or if there is anything I can do?