Two ways to prevent pregnancy are the use barriers (condoms) which has a 98% success rate of preventing pregnancy and the other include contraceptives which ranges on the type taken but generally has a effectiveness rate of more than 99% if taken correctly.
I would tell him that his health problems are completely confidential and that I would not tell his wife. If the wife asked me, I would say to talk to your husband he will explain everything.
In my personal experience In order to stay fit I do ballet and tennis. Those two things have helped me stay healthy and fit as well as creating hobbies! I also want to mention that I take vitamin supplements just in case if I am not for filling my normal vitamin intake from foods. So for example I take some vitamin C powder! I think it’s extremely important to work on your health and your physical activity because later in life all these things will affect you in a positive way so you won’t have to worry too much of your health considering the fact that you have been working on your health for the past years. I’ve also read that eating healthy can help you age backwards so you’ll look much younger at the age of 50 then you would if you didn’t take care of yourself physically. <3 have a great day
