I don’t get why people are saying she murdered his ego. what does it have to do with him what she got what she wanted?

The way Lucho approached that conversation was him saying that until Juls took advantage of Val, Val was fine and happy with Lucho. That if it hadn’t been for Juls interfering, Val would be in love with and satisfied with Lucho. 

Val was basically saying, nope, it wasn’t her pursuing me and taking me from you, I went after her, implying how little she felt for Lucho.