Dodger , your jury could have convicted the man of attempted rape, though only rape was charged on the indictment before you. The full offence necessarily includes an attempt; an attempt which proceeds to success; so the law says that where the success isn't proved the jury may convict of the attempt. It would be absurd if a man charged with rape walked free, acquitted because he'd attempted it but not succeeded.
But the judge may have thought this was an all or nothing case and didn't direct on this possibility. If the defence was seen as one of consent, it wouldn't matter whether there was an attempt or full sex, because the act was consensual in either case. And not capable of doing the deed may translate as not doing enough to constitute an attempt in law, anyway, whatever the state of mind of the parties.
The judge evidently didn't direct you on this