u/LaylaLost

I’ve had this Bird of Paradise for several years now. It’s placed right by the window but I’m wondering if it’s not getting enough sunlight? Over the course of the last few weeks, one of the large leaves has yellowed and looks like it will die. I fear other leaves are beginning the early stages of yellowing as well. Except the leaf with the most direct sunlight which looks perfectly green. 

Does the plant need to be rotated? Maybe being overwatered? I water it once about every 2 weeks. Fertilize once a month. Spritz it’s leaves with water twice a week. Is there something I’m doing wrong here or not doing? Confused since I haven’t really altered the care for it much. Any and all advice is welcome!