Jimmy has given some good advice. Separate them, let the female settle in, then try to feed her again. Also, make sure you are offering what the seller said they were feeding on. If they were feeding live pinks, try live pinks. If they were feeding frozen/thawed pinks, offer frozen/thawed pinks. Many breeders feed live because they also raise mice, while most small scale hobbyist like frozen/thawed cause its convenient. However, I think the stress of living with the male causing her to go off feed is the most likely culprit.
If all else fails after a few attempts after she is housed separately, you CAN try to tease feed her. The easiest way being to simply hold the snake in one hand with her head and about a third of her neck/body sticking out and tap her gently on the nose with the pinky held in your other hand. Sometimes they snap at the pinky and hold on, and then start to swallow once they realize what it is. This appears to be the least stressful method of "force" feeding. It may take a few trys, but works fairly well.
Good Luck!!