When they moved back, they lost legal recognition of their marriage and began encountering a host of difficulties, such as having to prove they are their son's parents during hospital stays and battling auto insurance companies for seemingly mundane things such as the marriage discount.
Newson said current Florida law undermines the commitment she and her partner made to each other.
"We want the state of Florida to recognize our marriage and our family," she said.
ACLU of Florida Executive Director Howard Simon said same-sex couples suffer discrimination in many ways. Examples include problems getting spouses covered by health insurance, difficulties with inheritance rules and retirement benefits, and problems with workers' compensation benefits.
"There is no rational reason for the discrimination that Florida inflicts on married couples," Simon said.
The lawsuit, filed late Wednesday in federal court in Tallahassee, names Gov. Rick Scott, Attorney General Pam Bondi and other top Florida officials. It asks a judge to declare Florida's refusal to recognize same-sex marriages as an unconstitutional violation of equal protection and due process rights, said ACLU attorney Daniel Tilley. The lawsuit also asks for a ruling requiring the state to recognize the marriages performed elsewhere.
State officials did not immediately respond to requests for comment.
Seventeen states and the District of Columbia allow gay marriage. A separate lawsuit filed earlier this year in Miami-Dade Circuit Court is challenging the ban on same-sex marriage that Florida voters added to the state constitution in 2008, one of many similar legal challenges around the country.
The Florida lawsuit follows a decision by Kentucky's attorney general earlier this month not to appeal a judge's ruling granting recognition to gay couples married in other states. Kentucky will pursue the appeal using outside lawyers.
Several federal judges have issued rulings in support of same-sex marriage since the U.S. Supreme Court's decision in June struck down part of the federal anti-gay marriage law. Two of the rulings striking down same-sex marriage bans in Utah and Oklahoma are being appealed to a federal appeals court in Denver.
Joining the ACLU and the gay couples in the Florida lawsuit is the SAVE organization, which advocates for rights and protections for people of all gender identities.