You're not messing up, and you're not stupid. Your bf is just a guy who likes to whine. I really doubt if people like that ever change. Though they can be smart about who they pick to whine at. He knows you have your heart set on pleasing him, so he knows he can unsettle you by saying, "Nope, what you did just wasn't good enough." He probably doesn't whine too much at people who really don't care how he feels about anything. Since you care for him, of course you care about pleasing him. But you need to decide that, if you make a good faith effort to do something nice for him, you're not going to feel bad, if he picks it apart with complaints. Of course, you will be disappointed, but don't let him totally bring you down. Tell yourself, "I did what I could, and that's all I can do." It wouldn't be wrong to flat out tell him he's being rude. He is being rude. You have a right to hold him to some basic standard of being decent toward you. He's like a petulant child. Treat him as such. Tell him like you would a mean little kid. Say he better either thank you for the effort you make, or not expect you to do anything.