Complex sentence: Vallejos was Iván Cabrera's girlfriend, but they separated in 2010 after her entry into Calle 7, and she began a relationship with Francisco "Chapu" Puelles.
Split into simpler sentences: Vallejos was Iván Cabrera's girlfriend, but finished their relationship with him in 2010 after her entry into Calle 7. Then, begins a relationship with Francisco "Chapu" Puelles.