I'm a mama bear to my friends too. There's a difference between taking care of friends low on their luck and grooming people into dependency. There's a difference between a charity case and someone who is mid twenties pandering to teenage girls with a daddy complex. A normal twenty four year old has nothing in common with a 16 year old. It a longer story than all that, but in short his White Knight syndrome is many parts avoiding his own growing up, ignoring his own issues and problems and weaknesses by making it a point to seek out and cover his own with those of other people. We knew we were both in a shitty place and we helped each other, which turned into something more. Was he there for me during a rough time? Sure. But to live with me and be in a relationship for over a year, become each other's rock and support system... Basically I split from my ex of six years as he lost his fiance of three, everyone took my ex's side becsuse I kept our issues to myself and he aired all the dirty laundry on Facebook for sympathy votes. It was a long term relationship where he continued to let me be the provider, never was in my corner, etc. So after that I make this friend who is the total opposite, personality wise, going through similar bad times, introduces me to a whole new group of friends when I was alone, has my back, we help each other trust someone is there to lean on. Eventually we become more as we develop a serious bond, and then he cheats on me with a teenager becsuse he's insecure and overly protective of women around him to the point that he makes inappropriate connections with them. Thus all of our mutual friends are put in an awkward position, as are our roommates, and this girl. Don't justify a scummy persons actions becsuse they were "there for me during a rough time." Yes, every relationship had its purpose. But I think it's pretty low for both people to go through those things together and then one of you break the bond of trust to "save" someone else. That's exactly what he told me when I busted him. He had to save her. He told me I was stronger than him and it scared him, he didn't like that I could see his damage. So he cheats, and it isn't worthy of an excuse. Best part? The girl he was seeing right before we became friends, his fiance? Their relationship ended because she cheated on him. I learned a valuable lesson, which is stay away from romantic entanglements shortly after long term relationships. But that doesn't make him any less of a douche, and it doesn't justify cheating.