First of all lostsoul214, I'm sorry for your pain. I want to address a few things from your post:
I shut everyone out in my family and the worst part about it is that I shut her out. I didn't realize how selfish I was being when I did this.
Maybe you were selfish, I'll take your word for that. But not nearly as selfish as this:
she has been having an affair behind my back for about 4 months.
Not even close. You were trying to get through debilitating pain. Maybe you acted like an ass at times, but chronic severe pain tends to do that to people.
She was pretty much taking care of me.
As well she should. She's your wife, it's the obligation she took on. Her family had this right:
They believed that marriage is through sickness and health.
It's not just her family's belief, that's been the standard through the ages. That's why we marry, to find a partner to navigate through life with, through good and bad.
Gently, I know you are hurting. But unless there's more to the story than what you've posted, your wife's behavior is terrible. Basically, she loved the "good" you but dropped the "bad" you (bad in the sense of not being Mr. Fun anymore, through no fault of your own) like a hot potato. Talk about a fair weather friend. And she's your wife.
Yet you see yourself as the selfish one, and her as a "strong woman." She's not strong, she's weak. And she gave into her weakness and is acting like a selfish brat. Her family obviously can see that, but you can't yet because you are desperate to get her back.
Be careful what you wish for. She has a lot of growing up to do before she even comes close to earning her way back into your life. For starters, she needs to go NC (no contact) with the OM (other man). Anything less should be a dealbreaker for you.
Please read the Healing Library and find the part about doing the 180. I'll edit this post in a sec and give you a link. Best wishes. Sorry you found yourself here friend, but I know from experience that you'll get a lot of help from the good folks here.
ETA: Here's the link, see Question No. 11:
http://www.survivinginfidelity.com/faq_bs.asp#FAQ11
[This message edited by Sal1995 at 4:17 PM, July 31st (Wednesday)]