Despite Lena and Martin getting along as co-parents, they must determine the best way to orchestrate Milo's upcoming birthday festivities based on their new system of boundaries. Meanwhile, Oliver is pleasantly surprised when Jenna shares a birthday invite with an unforeseen guest. Elsewhere, Maya takes matters into her own hands and reveals a surprise guest of her own.

Lena and Martin choose to share the house for the summer while the children are away at camp despite Lena's reservations, but soon realize it might not be the worst idea. They collectively agree to throw their annual backyard pina colada party where they will celebrate their independence from their children. Elsewhere, a friendly face returns back home and Martin can't help but see it as

Martin and Lena are thrilled when they hear that Mae has won the lead in the school musical but are surprised to learn that she has been confiding in the school psychiatrist, Dr. Rydacto, about her feelings toward how not divorced they are acting. Meanwhile, Martin has reservations about how fast his relationship with his girlfriend is going and asks Mason for girl advice.

With this being Martin's week in the house to take care of the kids, he discovers that daughter Mae finds his parenting skills to be lacking and a bit sexist. Meanwhile, Lena's time in the garage gives her time to contemplate going out with a handsome doctor and perhaps taking the relationship to the next level.

Lena goes out on another date with Wes, whom she's smitten with; but unbeknownst to her, Martin is doing his best to take care of a sick Milo. Meanwhile, Maya makes a decision on whether or not to become a single mother.

Unbeknownst to Lena and to her dismay, Martin starts to date a familiar face and surprisingly begins to see the world of relationships through brand-new eyes. Meanwhile, Lena tries to show she's a good role model to her kids by proving a point and faking a night out on the town.

While Lena gets ready to go out on a first date with a handsome man whose sexual chemistry is undeniable, Martin finishes his dance lessons with Charlotte and attempts to try to fix things with Lena on what would have been their 16th wedding anniversary. Meanwhile, Mason is being teased by his friends for not being as sexually active as they claim to be; and to prove that she would be a good mom, Maya attempts to watch over Lena and Martin's kids, with questionable results.

After breaking the news to friends and family about the divorce, Lena has to deal with her son Mason's growing pains; Martin secretly tries to atone for an oversight and surprise his ex-wife.