Yes, My Husband Passed Away 2 Years Ago. I Have

Yes, my husband passed away 2 years ago. I have been dating an old family friend and we have gotten to the intimate stage of our relationship. He makes me very satisfied, however, he gets a firm erection but cannot climax. Within 20 minutes or so, he is ready to go again.......and I am beginning to think he is pre-occupied with sex. Is this a normal thing for a man at the age of 78?