My gentleman friend and i are in our 70s. he refuses to use a condom. does that put me at risk for diseases?

Small risk: At this age there are very few diseases that might be transmitted sexually. Most would be manifest and if you gentleman friend does not think he has any of them , it is likely to be true. Condoms are, however, an aspect of mutual trust and respect so he should be a little more receptive to discussion of your fears.

Female condom: If your partner does not change his mind and you are concerned about stds, you may wish to use female condom.