Reality check 1: While I am not a fan of how you dealt with this, your wife was extremely insensitive. It's hard when my partner shuts down and shuts me out, and while I get that it's how some people process, it doesn't make it any easier for me to handle. I get why your wife was upset about this, but her response was unacceptable. Your niece/nephew just died, you are allowed to mourn and shaming you for that is a really awful thing to do.
Reality check 2: You are not asking too much to have mutual friends with your wife. I would not be comfortable having my spouse out partying with people I do not know. I am not a jealous woman and while my husband is certainly welcome to do whatever the fuck he wants to do, there are consequences to his actions. If he went out with a bunch of people that I was forbidden to meet and then got upset that I was not happy about it, he'd be sleeping in the guest room until we figured out separate living arrangements. He's my husband, I want to be around him. If I could choose anyone to hang out with, most of the time it's going to be him. Sometimes I want to hang out with my friends without him, but most of the time, I want him included. If he doesn't feel the same way, we've got a problem.
Reality check 3: Eeeh, I'm torn on that one. Personally and long story short, my parents are in a similar situation financially and will be in deep shit once retirement rolls around. They've done some pretty stupid things and I'm not sure I am up to enabling their poor money management by throwing more money at them, even if we could afford it. I have my own retirement to save up for, dammit. She has a valid stance, but this is a topic of discussion, not something that one person gets to decide. The problem here is not whether or not to help out your parents financially, it's how she isn't willing to consider a compromise.
As for the rest--this woman beats you, emotionally abuses you, and treats you as her housekeeper while she cheats on you and expects you to be ok with it. Why are you with her?
When you are at a spot like this in a relationship, you have to ask 2 questions. Does this person bring out the best in me and add positive things to my life? and Do I bring out the best in this person and add positive things to their life?
In both cases, the answers are no. You are being abused and your life has condensed to coping with that. You have nothing other than keeping house, going to work, and trying not to make her mad. She runs over you because she can, and she also gets a clean house, meals when she wants them, and someone who is eager for her attention when she feels like it. You're her backup plan, when everything else "better" is not available. You're like a neglected Labrador, desperate for her approval and affection while she mostly ignores you unless it's convenient for her.
http://www.helpguide.org/articles/abuse/domestic-violence-and-abuse.htm
Look through this and see how many ring a bell.
Your wife is in a bad spot. She's not necessarily a bad person, but she is making the same choices that a bad person would make. If a person does that long enough, they turn into what they are emulating. She's got something fucked up going on in her head and her actions are showing that she isn't capable of being with you in a way that's not hurting you.
You deserve better than that. Pack your bags, find a roommate, and start the divorce process. Use the internet to find resources in your area to help you safely exit this relationship. it's going to be hard, but in a year, you're going to look back and wonder why it took you so long to get the courage.