Sorry to hear what you are going through just now. Sadly, it is NOT uncommon. In most relationships, at first, sex is fun and frequent. With the passing of time, frequency tends to drop off, and interest wanes. I do not think that this is a conscious choice on your husband’s part, just a natural progression.
I am perfectly sure that there is nothing 'wrong' with you. You have tried the standard approaches to this sort of problem, obviously without much success.
Firstly, it would be useful to persuade him to have a physical checkup. It is possible that is hormones are out of balance, and low testosterone can be treated. It may be too that he is over-stressed, over tired or suffering from depression.
If there is no physical reason, then the problem may well be psychological, in which case I think you would find a sex therapist very helpful.
Secondly, it's time for some home truths - he needs to understand quite clearly how this is making you feel - unloved, unwanted, rejected I suspect, and also that you are not prepared to go through the rest of your life like that. I suggest that you tell him that unless he agrees to counselling with a sex therapist, you will have to consider what your future is going to be.
He is an adult and must understand about actions and consequences. We humans only indulge in behaviour that bring reward of some kind. Only when that reward (whatever it might be) disappears, or the consequences of our behaviour promise to be unpleasant do we consider changing what we do. Home comforts come with a cost, and that cost is AT LEAST as much affection as he shows the cat – or he can get the cat to do his laundry!
He needs, therefore to be given a reason to change.
Give him choices, and make sure he understands the consequences of their choice – and always follow through. If you don’t he’ll just get confused.
Never, never be blaming or accusatory. Stick to facts, tell him how you feel about his behaviour, and make sure he understands that while you love him, his disinterest Is hurtful and will not be accepted for much longer.