Women I now understand that old saying "can't live with them.."

I dont understand how or why certain women are never satisfied. Women can side with one another even if they really dont have a strong relationship with one another or a relationship at all. I think I am to the point were I would be happy in my life knowing I am going to be alone. I have been doing a horrible dance with my partner in crime of the last 5 years and I feel like it may not last to much longer. It's the worst feeling in the world to know you may be close to losing the only true friend you have ever had. On the other hand I cant take much more of being told Im constantly flirting, or feeling that they're never satisfied, cant get over things quickly, but they expect me to and then forget everything I constantly do for her. I by no means physically abuse her, but I think with all the constant let downs I have not been able hold back my mouth. I dont feel that this relationship is far anymore. Its more of becoming all about her and I take the blame for that because I have tried to be the best husband, boyfriend, friend. I try listening to her to helping her get the things she wanted in this world. I know by giving her what she wanted has made her someone else. I by no means deny my blame in this. I never thought I would be the person that would become the screw up in my family, the one that became my father. He left me fatherless, never finished school, always seemed to never want to take responsibility. I always thought my brother would be the one to fall into this mold and now I find myself shocked as I look up at the hole I've created for myself. I see these people that are supposedly happy and wonder if they are really happy or are just putting on a face for the masses. All I and I'm sure everyone else have ever wanted is happiness. I just wanted friends (not tons just a few true ones) that I can count on and have there in my corner. It doesnt appear that it will ever happen. Seems like I am going to be like Bruce Banner (the HULK) forever wondering the world alone.