JimmyChoo, I would recommend the adage "never say never." Nobody fully understands the myriad pathways your recovery might take. If your worst case emerges and you never get a natural erection again, I personally would advocate the use of the pump for two purposes (a) all kinds of sexual pleasure, both alone and with a partner and (b) to keep the spark alive - as you allude to, there is no need for those sexual urges to stop. Mine certainly haven't even though my erections are few and far between. And while I am lucky to have a supportive partner, we have both adapted to new ways of being sexual together. And I still get upset and confused when I am aroused and limp, or fade away at the critical moment, two and half years after treatment.
Is it frightening, frustrating and emotionally challenging? You bet it is. As a man, probably the biggest combined physical/emotional challenge I have experienced in my 64 years on this earth. Looking back, I have learned a lot about coping with things not going the way I want them to go, and still choosing to enjoy my life including my sexuality.
About being single and dating, here's a great resource from a wonderful single man who says his partners actually really like being able to "dial up" the hardness and size of his erections using the pump. And he is not alone in reporting this - just that he has taken the time to write extensively about what it is like getting over those edges you anticipate, like telling a potential new partner about your non-standard-issue male body. Visit this blog for honest, practical stories of prostate cancer and the single man https://edysfn1.wixsite.com/prostateadventures