My husband has beginning dementia. I observed he has started to watch porn on the tv. I think it's disgusting, it's horrible, please advise.

I would agree to drop all traditional programming and only have controlled programming on apps. Have an account for him that blocks out programming that would be considered mature on Hulu or Netflix (I dropped my regular sat and only use apps now and it has saved me at least $200). I think that with people with dementia their social filter starts to go away so nothing is really inappropriate anymore as they don't know they are being that way.

I agree, you should block or drop those channels. If you have to give up cable or tv altogether, you can learn how to stream on your own device (iPad or laptop). I don't watch "traditional" tv anymore, only streaming.

You have good advice below. If that doesn't work you may need to give up the internet. I hope not, as I imagine it is a comfort to you.
You could also consider having your own password protected computer and destroying his. He is in jeopardy legally if he is accessing porn of some types, esp child porn.

Put the parental blocks on the channels that have porn and the ones that are pay-per-view ordering. This is not hard to do. Then you don't tell him the access code to remove the parental locks.

Inappropriate Sexual Behavior, or ISB, is common with dementia and can be treated with medication. Call your husband's doctor to discuss the matter. The ISB can also show up as a heightened sexual desire for you and an interest in constant sex, whether he's able to perform or not.

Good luck to you.