TBH I am not sure, but I have heard that the most important time for the pessaries to be absorbed is the first hour after insertion. Some clinics recommend lying down for half to an hour after inserting them to allow them to absorb although my clinic didn't. So perhaps it would be best to DTD just before you insert the pessary. This is just a guess though. Why not ring your clinic tomorrow. They will have heard everything and this is a fairly normal question IMO.
I figure they would have to be fairly benign for your partner too otherwise they would tell you abou it, but maybe someone else knows more about it. And even if he finds it a bit strange you are the one that has to put up with the goeyness all day everyday