Alyssa Salerno has filed legal docs asking a Florida judge to formally establish her ex-fiancé Alex Kompothecras as the dad of their daughter, lock in a custody arrangement, and order child support … TMZ has learned.

According to the petition, obtained by TMZ, Alyssa wants the court to establish Alex’s legal parentage, award shared parental responsibility, and implement equal time-sharing. She’s also asking for child support to be calculated under the Florida guidelines and made retroactive to the date of their split.

Alyssa is further requesting that health, dental and vision insurance be maintained for their daughter, with uncovered medical expenses divided proportionally. She also wants extracurricular activities and any private school costs shared.

It’s important to note the petition does not allege any abuse or misconduct … it centers on formalizing custody and financial responsibilities through the court system.

As fans of “Siesta Key” know, Alyssa and Alex began dating in late 2019 while on the MTV reality series, eventually getting engaged in July 2024 and welcoming their daughter in June 2020.