Ok, everyone's joking but I'll share my experience. Dh wasn't on accutane, but he was getting chemotherapy through September and chemo meds are considered dangerous to fetuses' as well and are present in bodily fluids. We actually didn't share a bed or bathroom during this time, but doctors said that we COULD, it just depended on our comfort level. They said for him to always flush the toilet with the lid down, and wash his hands carefully.
We also used condoms until we were confident that the drugs were out of his system.
Again, not the same meds. I honestly found that most doctors were clueless about secondhand effects for pregnant women. I had to contact a LOT of people to get a straight answer about what was and wasn't safe.
Chemo meds are probably more potent in smaller doses than accutane, but if you feel more comfortable using a condom, do it. We were specifically told to use condoms by DH's oncology nurses because the meds would be present in his semen and the baby would be exposed during sex.
So there's that.