Lauz4841,
The Aplastic Anemia & MDS International Foundation (AAMDSIF) offers advice on
sexuality and intimacy. These types of questions have been addressed at sessions at some of their Patient Conferences.
Here are the slides from one such session.
As DanL says, when men are anemic, as they often are with MDS, the blood supply required for physical activity, especially this type, is diminished. But experts offer tips that can help. Some are obvious, but there are others you might not think of, such as avoiding sex while digesting, because both are powered by the blood supply.
If you contact the AAMDSIF, I bet they could identify other sources of advice for you.