Well how sex is tied into our deeper self is always complicated. Nobody should ever feel obligated to have sex just to keep an relationship going. Doesn't sound like a very healthy relationship even if you put aside the sexual aspect of it. Anyone who would give a person a time limit to get better is not someone who is really caring and understanding.

You abilit to help her is going to be limited to her wilingness to accept your help. Offer what help your willing to give, but don't push, and don't feel responsible for things that are not your fault (not always easy to do).