C, he doesn't find me attractive anymore!
As humans, we often may have the tendency to assume that we are the cause of things or blame issues on ourselves. In this situation, that manifests as you assuming that your partner's low sex drive (or rather complete lack of it) may be due to him not finding you attractive or no longer loving you. While this is an understandable anxiety and one that many of us (myself included) have felt at one point or another, I would encourage you to not look at the situation this way.
The first step here - as others such as
@emkee_reinvented put it - is to talk to your partner. You cannot read his mind, and even us psychics here at Bluelight cannot do so either. The only way to know what your partner is thinking and know why you guys have not been having sex is to ask him. Tell him that you've noticed his sex drive has been much lower for the past year or so and ask him about it.
A, has heart failure so meds could be affecting him therefore making him lose his confidence in the bedroom
I'm not sure how old your partner is, but some combination of age, the heart failure (As
@Fiori di Bella said), and the medication may be causing this.
In men, testosterone begins dropping after age 30 (but men in their 20s can experience hormonal issues in rare cases) and this can often lead to noticeable sexual issues by the time a man hits his late 40s or his 50s. These issues usually involve decreased energy, massively decreased sex drive, erectile dysfunction, etc.
Many cardiovascular medications also cause erectile dysfunction. Both myself and a friend of mine (who called me up to ask if it was normal for sleeping pills to break his dick) experienced this when we were prescribed different alpha agonists for sleep + trauma-related-nightmares, and we were 17-18 at the time. As
@tubgirl.jpg said, beta blockers are even more notorious for this issue.
B, maybe this is normal after so long
Having less sex is normal, but a complete lack of it is generally either due to psychological/physiological issues or a relationship issue. I wouldn't say that it is a normal and healthy part of relationship dynamics (unless neither partner has an interest in the relationship being/remaining sexual), but it certainly is common.
(No he won't really discuss it) how can I increase his appetite? Yes I wear the lingerie & play little games to get him going but no cigar! Help!
Tell him that this issue is important to you, that you want to have a sexual relationship, and that you need to talk to him about it. The issue likely doesn't have much or anything to do with how much you turn him on, and seems to mostly have to do with him. So outside of talking to him and ensuring that he knows that you will not judge him for whatever his response is, there isn't much you can do here.