Oh I went through something really similar with one of my pairs with an elder male bun! We moved and he was mounting OBSESSIVELY. I had to separate them overnight because she wasn’t able to eat or rest and I was worried he was going to have a heart attack.
I would recommend having him checked out by a vet as a first step, there can be bladder issues that can trigger excessive mounting (infections or bladder stones). I did this with mine and he got the clean bill of health, so it turned out it was triggered by the move. Sometimes when you move they need to resort things out a bit.
I would continue to separate them for periods of the day to give them both some rest, but then allow them to be together in a more neutral space. Giving her some hiding spots and tunnels to escape from him should also help. In my case things calmed down after about a week or two.
I also realized I had been feeding a lot of dandelion, which is a diuretic and is very high calcium (parsley is as well). I haven’t been able to find any info on this, but I’ve noticed my boy mounts WAY more when he’s eaten dandelion, so I’ve cut it out of his diet aside from occasional treats.
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The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.