She still carries out her strong feelings for Edmond Dantes. When she finds out The Count Of Monte Cristo is Edmond Dantes, she tries to convince him to love her once again, as Edmond Dantes. Even though the Count refuses to have her still think of him as Edmond Dantes(even though he knows he is still Edmond Dantes), Mercedes still loves him more than he thinks.
When Mercedes finds out Mondego was responsible for framing Edmond, or the Count 25 years ago, she says her farewell to Mondego and gets shot by Mondego, but later manages to survive.
Towards the end of the series, it is later proven by her son, Albert that Albert was The Count of Monte Cristo's son, not Fernand's.