The two were engaged on Christmas Day, CNN said Tuesday.
Maloney and Florke have been dating for 21 years since meeting in line outside a dance club in New York on Maloney's first night apartment hunting in the city. A longtime aide to several prominent Democrats, including former President Bill Clinton and New York governors Eliot Spitzer and David Paterson, Maloney is a freshman congressman representing the state's 18th district after winning a narrow victory over Republican Rep. Nan Hayworth.
Maloney will be the second lawmaker to marry a same-sex partner while in office, The Hill said. Former Rep. Barney Frank, D-Mass., married his now-husband in 2012.
Rep. Mark Pocan, D-Wis., married his husband in Canada in 2006 before entering Congress.
He offered Maloney and Florke congratulations via Twitter.
"Congrats to my good friend @RepSeanMaloney on his engagement. I wish you two many more years of happiness," Pocan tweeted Tuesday.
Maloney's office said a wedding date has not yet been set, CNN said.