A recent (last December ) report came out with some very pertinent information on this topic. I hope @AnneWimsey that you and your partner gain wonderful benefit from the report.
[verywell.com]

Well, I cannot answer the medical or man stuff, but YAY FOR YOU!!!!!!!!!!!!!!!!!!

Ask HIM. Best not to assume anything. Many people taking heart meds have few, if any , limitations on their activities.

Thank you everyone for the positive outlook...i guess I am just a big chicken about these things, was married for over 30 years to a man who disliked sex ( with me) so I am kind of a virgin at this point......

Ask Dr Ruth

his doctor should be able to advise on sexual activity

I may be female but know a little on the topic.

1. First question is would you both like to.
2. Heart meds is an awful broad term and doesn't necessarily preclude vigorous exercise. My ex husband was on them in his 40s ended up with a stent to match, never stopped him. If 1 is yes get him to bring a note from his doctor.
3. There are options other than the missionary position that require less cardiovascular effort, either on his part or both.
4. My aunt and her boyfriend were still active in their late eighties.
5. Just go with the flow, experiment, enjoy yourself, falling asleep curled up together is just as valid away to "wrap it up" as anything else.

Bonding through interests is a lasting proposition. Bonding based in the physical is temporary. I have found that enjoying one another's company is far and away more fulfilling than anything else. My wife is 15 years younger than I. We married based upon our friendship. When sex became a non issue, mainly because of severe menopausal changes in her, I can honestly tell you that it was a little difficult at first, but our friendship, our ability to talk with each other about anything, and our interests formed the cement that held us together. I can't imagine being with anyone else and I think the feeling is mutual with her. I can also tell you that our friendship is probably a large part of why we have had few arguments in all our time together, and those we did have were brief and always resolved.

Sounds like a chat with the doctor is in order. This is not something where "oops" is an answer.
Part 2: Happy endings do not require orgasmic delight. Just laying back and letting things calm down in perfectly OK. In fact, that is my preference because ..... well... because its OK. I'd add that because there is no real sense of urgency it becomes an all-evening activity, with breaks, snacks, saucy talk, and even a nap or two.

If he is fantasizing with role-play , then he is healthy enough for the real thing . I wouldn't expect any pony rides though . . . Simply ask the man if he's up for the real thing . If he says yes . Meetup for a brisk walk about a park , or somewhere public . Join the same gym , & see for yourself . At any age , look before you leap , & give someone benefit of the doubt , if they carry themselves in a civil , yet interested manner . Best of hopes