Aside from Wendy (Maggie Siff) and Wags (David Costabile), Bobby can't vent about his professional woes to anyone. And as of the season 4 premiere, it appears as if Bobby is composed of entirely professional concerns. Lara (Malin Akerman), Bobby's wife, is nowhere to be seen. Last season tracked the dissolution of Bobby and Lara's once strong marriage. If the season 4 premiere is any indication, the Axelrods are no more.
For the first two seasons of Billions, Bobby's domestic life was a consistent segment of the show's action. After a day of high-powered manipulations, he'd speed down the highway toward Connecticut, where there was frequently drama of another sort. Lara and Bobby used their enormous closets as war rooms, where they carried out strategic discussions about a) familial obligations or b) holding onto their fortune. His two sons flitted into scenes like seedlings of future Large Adult Sons; if you blurred your eyes, you could see them wearing Patagonias and playing pong in the living rooms of their Ivy League fraternities on a Tuesday night. These scenes were essential reminders of Bobby the Man, not just Bobby the Man of Industry.
But Lara's role in Bobby's life (and thus the show) diminished significantly last season. The fact that Lara announced that if he got arrested, she'd move herself and the kids to California probably didn't help.
The last time we see Lara, she's helping Bobby grapple with decision for comp — because she knows his mind better than anyone else, and because she was Axe Cap's largest investor. At the time, it seemed like they were on a tenuous path to reconciliation (they even kiss). Now, it's obvious it was just two were wrapping things up with the fondness of two people who know each other better than anyone else.
So, is Lara coming back to Billions at all? Yes — but we'll have to wait a few weeks for our first sighting of her steely face. According to IMDb, Lara will appear in episode 6, "Maximum Recreational Depth." Billions' IMDb pages have yet to be updated for further episodes.
Part of Lara's absence may also be explained by Akerman's schedule. Akerman was just cast in the NBC pilot Prism. Her Billions family is supportive — co-star Kelly AuCoin (aka Dollar Bill) commented a heart on her announcement. She's too busy to be a wife on the sidelines, waiting to be summoned when Bobby has a temper tantrum. She's a lead now! Maybe in another set of TV scheduling circumstances, Lara would be back in Bobby's life. But Akerman's headed toward stardom, and no happy Axelrod marriage is worth depriving her of that.