Little is known of Wendy and Jax's history together, besides the fact that they were drinking buddies that had "great sex". Gemma however pushed the idea of marriage on the two because of her desire to have grandkids.
She is a recovering drug addict who used methamphetamine during her pregnancy. After learning the reasons for her grandson's birth defects, Gemma gave her drugs and the instructions to commit suicide via overdose. Gemma states she will never allow Abel to call her mommy and she would use her ex-daughter-in-law's drug addiction to ensure she never have any contact with Abel. Wendy went to Promises rehab and spent time in a sober living facility afterwards. She longed to reunite with Jax, believing that the stability of her family would assist her recovery. Gemma, desiring to destroy her son's relationship with Tara, promised to help Wendy reunite with Jax. After a rift between Tara and Jax and the murder of Donna Winston, Jax and Wendy reconciled and were seen making love. She was last seen at Donna's funeral watching Tara kiss Jax.
Wendy returns to Charming with the intention of getting to her son. She says Abel deserves to know the truth. "Out of respect" she asks Tara's permission first, causing Tara to have a bit of a breakdown. Wendy uses the argument that she is a recovered addict who turned her life around and would probably be seen as the most stable adult in Abel's life if she should chose to pursue custody; giving Jax and Tara the ultimatum to let her see Abel or risk losing him all together. She's gotten much more calculating, and may prove to be a force to be reckoned with in future seasons. Wendy is later seen at Jax's home. Chuck Marstein answers the door and informs Wendy that Abel is in his room. Wendy walks to Abel's room where she is met by Gemma. She divulges that she is now interested in women romantically and lives with her new lover in her apartment. After she threatens Jax and Tara, Jax shows up and threatens her, if she ever tries doing anything against him, or Tara. To make his point, he shoots her in the arm with a speed ball (ouch).
Wendy returns again, conspiring with Tara in a plan to gain full custody of Abel and Thomas if Tara should go to prison. To do this, Tara has Wendy feed Gemma a series of dirt and lies in order to make her agree to help Wendy get full custody. The guilt of Tara's methods for custody eat at Wendy, causing her to relapse back into heroin use. She is found unconscious by Nero and Unser in her apartment and is taken care of by Gemma, who helps to get her back into a rehab facility.
Wendy returns to her apartment to find that Juice has been staying there while on the lam from SAMCRO. Wendy helps Gemma and Unser hide Juice from the club and she continues to help out as a sitter for Thomas and Abel. In the episode "Faith and Despondency", Jax finally confesses to Abel that Wendy is his biological mother in order for Abel to have a mother figure in his life following Tara's death, leaving Wendy grateful to Jax for telling the truth. When Nero expresses his desire to move to his uncle's farm to Jax, Jax suggests that he bring Wendy, Abel and Thomas with him. Surprised, Wendy agrees to go with Nero. In the series finale, Jax tells Nero that he is "going away" and that he is selling his house and the garage and giving the money to Wendy so she can raise his sons. He requests that Nero tell Wendy the truth about everything. In their final meeting, Jax says his goodbyes to his sons and tells Wendy she's a good mom and that he loves her. Wendy senses something is wrong, and Nero promises to tell her everything later. She goes with Nero, Abel and Thomas to the farm, unaware of Jax's imminent suicide.