Sorry about your husband. I can understand this is all unsettling and you never asked for any of it.
However, Im glad you're reframing and reconsidering your stance as well as laying out some rules more clearly.
Have you considered Air BnB? Depends on area etc but this might be good money for shorter stays. So definitely not someone else's home. It is definitely your lodger's home if he's there full time. He isn't homeless, can have his post delivered there etc. Obv he doesn't have any claim on your house or anything but whilst he's paying to stay there on an ongoing basis, it is his home. It seems like semantics but I think accepting that point is quite key. If you really find that hard to swallow, maybe air BnB.
Let him know you can hear his conversations and ask him to use headphones or the handset. He probably didn't realise and will be glad to know. He doesn't know how sound travels in your house.
You said he could have occasional visitors. This is exactly what he has done. They weren't stopping you using the kitchen. If you want to limit the number, ensure prior agreement or for him to eat in his room when visitors do come, you need to tell him. Where we currently standing, he has followed rules. He isn't a mind reader.
To give the other side as the have been a few lodger stories, as a PP noted, people with lodgers often don't want lodgers, they want the money but not the person in their house. That isn't the lodger's fault. I lodged with a woman like that once. I wasn't perfect, I was very young ) generally respectful quiet and tidy) but christ, it was non stop and really quite depressing how much she scrutinised and complained and made up new rules. Random petty things like one day I couldn't keep my shampoo in the bathroom when I had been told that was fine, or I had to ring if I was going to be back after 10pm (I worked in a pub which she knew before accepting me). All the while, the stories I could tell about her. Christ.
First find some fair boundaries and express them. Then either accept you need to do this for financial reasons and try to feel more relaxed about having someone around (believe me, I know it isn't what you would have chosen) or find an alternative such as downsizing.