the reason why i always feel bad

i never seem to make her happy. ive made her cry so many times, and everytime, it gets harder and harder to bare with. i just want to see her be happy. but i can never seem to achieve that. and because of that, i feel bad and that makes her feel bad too. i just focus on the negative too much. its not like i want to, i just do. all of this is my fault, and everytime we fight over this, i feel as though its slowly affecting both of us. i dont want it to, cause i dont want to lose some like her. i love her, and i want to marry her