Radiation therapy has an immediate impact on destroying cancer cells but does not linger in the body. And it therefore does not expose your partner to any radiation risk. Similarly, there are no risks to your partner from the chemotherapy drugs you are taking, although during treatment a few chemotherapy drugs can be present in small amounts in semen or vaginal fluids. Ask your doctor if this applies to the chemotherapy drugs you are taking. If so, it may be appropriate to use condoms around the time you are receiving your treatment.
Some people even promise to give up sex as a sacrifice in return for a cancer cure.
Few religions support such a harsh view of either cancer or sexuality, and such concerns should be discussed with your priest, minister or rabbi. If you are wondering whether sexual activity would cause a problem during treatment, ask your doctor. The answer may vary at different times and for different people. But common sense, and a simple question to your doctor, may be all that is necessary. Communication, however, is just as important with your partner, if not more so.