Its beginning of episode 4 of world tour. Frollo feels uneasy around the girl on the other team. At first he correctly assumes that she just creeps him out but then Fren, who is on the 3rd team, sees this as a strategic opportunity* and exploits Frollo's inexperience with romance to make him think that he has a crush on her. At the end of the episode, Frollo confesses his false feelings to Mal.
At some point in this mini arc, Peter (who is on Frollo's team) gains the courage to ask out Frollo, but witnesses him kissing Mal of all people. Peter runs away while holding back tears. Fren, seeing Peter**, goes to find him and genuinely ask what is wrong. Peter sobs loudly and Fren comforts him, knowing only that the matter has something to do with Frollo. Peter's sobs become sniffles as he hugs Fren and he promises to form an alliance with him after the merge.
Over time, Malfrollo becomes more and more poisonous, specifically for Frollo. Being raised strictly Christian, Frollo thinks that splitting up is immoral and an affront to god. Peter witnessing what has happened to Frollo, tries to break them up but Mal likes having control over Frollo and keeps him at her side, leaving one of two options. A - Vote out Mal and have Frollo go through a makeshift rehabilitation process OR B - Vote out Frollo and hope that he sorts himself out.
He goes to Fren to ask for help with Plan A while explaining the entire situation from his perspective. Fren is internally screaming and feels really guilty because technically he is the reason for Peter's Heartbreak. Anyway Plan A succeeds a few episodes later, Frollo is successfully rehabilitated and Patfrollo becomes canon a few episodes later.
*After Mal's amazing performance in tta, Fren sees her as a massive threat and also she is mean to his friend O.
**Fren's team won the challenge but Mclovin is taking a nap and he snores very loud.
I love the energy here, you got a whole ass version on ttwt and I love to see it. Thank you for sharing your vision with us, malfrollo anon