Bird of Paradise, indoors, can be one of the most spectacular and easy of plants. The one thing it HATES is wet roots. It may not have been real strong coming from the grower - they often lose at least one of their stalks - but I can almost guarantee you kept it too wet. Or it was too wet when you got it, and you didnt let it dry out. The little yellow-green things in the soil are fungi, another sign of excess soil moisture. By all means, put it outside - no direct sun please - and only water it when the soil is almost dry, i.e. dig some up with a spoon and feel it, it should have just the barest trace of moisture. Dig way down toward the bottom of the pot. They often regenerate amazingly outside. And please, don't be afraid to try again. Most important, always feel the soil before watering. You can get a wooden dowel from a craft store, and stick it in along the outside edge of the pot, don't worry about damaging roots. It's just like testing a cake - if no soil sticks and the dowel feels dry, you can water; if soil sticks and dowel feels damp, don't water yet. Or you can use a spoon, but you need to get all way to the bottom of the pot. Also spray the leaves with mild soap and water (1 tsp soap to 2 c water) every couple of weeks, and wipe down, especially the underside of the leaves, with towels. This is to keep the spider mites under control. And sorry to say, they don't flower
in the house.