Canary won't stop laying eggs

I was given two canaries (one female and one male) by my cousin who could not care for them anymore and I've had them for about a year and a half. In April, the female canary had to be taken to the vet to have her leg band removed because it was constricting her. I had kept her in a separate cage from the male during that period and when everything was done and I put her back, she immediately laid eggs. Since then, she's laid many eggs and in most cases the eggs wouldn't hatch and in some cases, the eggs would hatch but the babies would die soon after. So far only three hatched. So I read online somewhere that laying too many eggs is not good for her and usually if the same pair keeps mating the babies would be weak so I decided to take the nest away after her last batch failed and she abandoned the nest. But she's constantly crying, tearing newspapers and flying to the area the nest used to be back and forth. I don't mind if she continues to try but I don't want that to lead to her dying or getting sick. Can someone tell me what I can do? Also, one other thing is that they are constantly fighting since she laid her first batch of eggs in April. The boy doesn't allow her to move freely in the cage and it seems like he wants to control the perches and pushes her to go down to the bottom of the cage. He also keeps plucking her feathers when she's not paying attention. I wanted to separate them but they both become upset when I do so and I always end up putting them back together. They used to argue before over food but never like this. I would be so grateful if someone could explain these things to me. They are yellow canaries. I don't know their age as I did not buy them.