I am not sure how old your rosebushes are. It can take 3 to 5 years for rosebushes to get their root systems well established. The blooms on the less established rosebushes will, on some varieties, not last very long. The rosebushes will also drop their blooms more quickly if stressed or in some form of shock. Stresses and shocks can be temperature related, water/moisture related, insect related or chemical applications related. If the roses are newer plantings, I would water them with some water that has both a product called Super Thrive and a root stimulator in the water. Water them with a fresh batch of the same mix the next 5 to 6 times they need watering. If the roses are older roses, water with water that has just the super thrive in it for the next 4 to 5 waterings. The spots on the leaves can be small insect damage points or chemical spray drift on the foliage. If insects a spraying with an insecticide may be in order. Check the foliage at night with a flashlight and you may find the insect culprit. If the yellow spots have a black spot in the center, it could also be Black Spot fungus. For fungus issues I use an earth friendly fungicide called Green Cure. It comes as a white powder that you mix with water in a sprayer. Two scoops per gallon of the powder with the scoop that comes with it is the Cure Rate and the rate I use all the time.
It is likely that a combination of diseases is affecting your rose. The leaf spots sound like rose black spot fungus. If your rose blooms fail before opening then a different problem is at hand, commonly referred to as rose balling. Links to help you are next. https://www.gardeningknowhow.com/ornamental/flowers/roses/black-spot-roses.htm