I want to remind you of something. Your husband is a GROWN MAN; he's not an infant. All along, all these years, he has had the choice to either address his issues and improve his marriage, or ignore his issues and destroy his marriage. HE is the one who made the choice to ignore his issues and destroy his marriage!!! HE chose that, not you. Now I understand that some men have erectile issues, but that does not preclude ALL SEXUAL CONTACT! He still has fingers and a tongue, and you could buy battery-operated toys or very life-like options to continue having a fulfilling sex life together. HE chose to disregard you and your needs, and further to blame YOU for his choice!!
So here's how healthy, mature adults work: We choose to walk side-by-side in life, but we do not NEED each other in the sense that we would "just die" if we weren't together. We behave in a respectful way. We listen to each other (it's a two-way street), and consider how our choice may affect our spouse. We consistently look at ourselves in the mirror and think, "What do I need to work on to be a better human?" and we do the work. We put our time and effort and money, voluntarily, into our spouse...also knowing that any day they could choose to end it all and we'd be done, and knowing that they are free to do so!! INTER-dependent rather than CO-dependent.
So he made his choice. HE is the one who chose to put himself in the position of having no one care for him, because all he had to do in order to have a loving wife who would be willing to care for him is set aside his pride, go to a doctor for his ED, do what treatment the doc suggests, do some individual counseling to address his issues of denial, and work WITH you as a team to have a satisfactory sex life. In other words: act as if your need for sex was reasonable and address it! That's it!! That's all he had to do, and he decided he didn't want to make that effort. Okay cool...the result of that choice is that he doesn't have anyone to care for him. Too bad for him that he's sick--HE CHOSE!!
If the two of you are living at a place that your parents own, just go file and straight up tell your husband you are divorcing him. Then have your dad help you get him off your dad's property. If there's a lease in your husband's name, your dad can notify him the lease is broken and give him a notice he has X number of days to move out. The end.