While this is a legitimate problem, it's really important to keep in mind not to frame this as a "her fault" kind of problem. You really need to keep that forefront in your mind because talking about this the way you are is going to come off like you're blaming her even if you're not and that's likely how she'd hear it if you told her.

You do actually need to talk to her though. It's a problem that's impacting your relationship.

You really need to stress that you're not blaming her, you're not upset at her, and that you're not trying to make her feel guilty about her health issues. Ideally you want to be framing this as you asking her for her input. You also need to stress repeatedly that you love her, care about her, and still find her attractive. If she feels that your love is conditional on sex, that's going to make her feel (rightfully) pretty terrible.

There may be some kind of arrangement that she is comfortable with where your needs are met (or at least more met than they are now) and she doesn't feel pressured, but that needs to come out of a conversation with her.

You will also need to be very, very aware and conscientious to avoid pressuring her for sex. It is not her responsibility to give you sex. There also needs to be care taken such that you're not framing this as "I need sex or we can't be together" because that is very much pressuring someone.

Be ready to do some reading, research, and personal introspection to see if there are alternatives that you maybe discounted before but now feel more ready to look at or if she makes requests. This is your situation, you need to be the one to take point on doing the legwork to work it out.