really hurt girlfriend

My girl has done her best to adjust to a ready made family 6 yrs ago. My ex-wife died suddenly going on 2 yrs ago and my 3 kids were home with us full time. My girl recently had brain surgery (no kids) and i've been doing what I thought was my best to be a good boyfriend and dad while my girl recovers. We moved an hour away from our old house for several reasons, one being close to my girls support system to prepare for the brain surgery. My 16 year old son freaked about the move and moved in with my ex-wifes boyfriend who was the guy who was banging her while we were still married. My middle daughter went to school in the new town for a semester but after we returned from the hospital said she wanted to move back to her old town and old school. Thinking I was sheltering my girlfriend from stress while she lay recovering from a massive surgery I made the dicision to move my daughter back to her old school but commute with me daily, I wanted to avoid seeing another child shatter my heart by moving out. My girl is now so hurt by me making that decision without talking to her that it seems impossible to make any right decision. My girl has always been emotionally complex (think complex like trying to understand how the Higgs field gives objects mass) and I've always felt I will never make her happy. We're at the point now where she thinks I don't love her and I'm at the point where I've all but given up trying to meet her expectations.....any thoiughts on how to recover from this?

You just have to realize that you HAVE done everything you possibly can do. It's not your fault at all.