SageM pointed to this ANN post announcing the return:
The wraparound jacket band on Sakurako Gokurakuin's 2nd Brave Star ☆ Romantics manga volume announced on Saturday that Gokurakuin's earlier manga Sekirei is returning as a regular series. Sekirei will resume in this year's 10th issue of Square Enix's Young Gangan magazine on May 2. The advertisement for the manga has the subtitle "Kanojo no Inai 365-Hi no Koto" (About 365 Days Without a Girlfriend). It further teases, "One year with his girlfriend gone. One year until she returns."