For what i see in my perspective,here what a reason ibelina do this :
1. Ibelina know Alejandro depends too much on her
2. she is reincarnated,and she following the Novel that she know,and she thinking what she do could change the whole Story,so she Run away and Alejandro can found with protagonist from the Novel
3. and she is right,she is a commoner ,Alejandro image will destroyed if he fall in love with his maid,so She doing it
on other ,why Alejandro want to keep Abe ,cause she is the only one loving him and care about him with full heart when he still cursed,for almost 10 years,and she is the reason curse Lifted ,by letting Alejandro Fall in Love ,thats why Alejandro cant let her go