Also the diaphragm has to fit exactly and will require fitting by a professional as they are made in different sizes to cover the whole area so no sperms slip by ;-). U will need a spermicidal preparation with it and insert the thing at least 10 mins B4 intercourse might happen. Then there's taking it out, washing it and putting it back in the box after

. Mine would at times flip across the room when I took it out of the box

like it didn't want to go up there in the dark

. Also if not cared for correctly they can become stiff and useless.
I had the contraceptive Pill successfully for 11 years B4 being sterilised. What's wrong with him using a condom? It is essential to be checked for disease, women in the their late 50s-70s are presenting at clinics with nasties so condoms are recommended even after child bearing years. Do not believe his sexual history at this point, men are not always honest!