Yeah, i have no idea about the chemo he's receiving, but the chemo my wife had, we were warned about. It's as much for your safety than his. But you need to speak to his team about this. But a condom needs to be worn at all times for both your sakes.

Even going to the loo, my wife had to flush with the lid down for a few days after each chemo, and flush twice. I hope you both get some sort of compromise.