It sounds more like he is a lazy, disrespectful arsehole, rather than his weight, that is merely a symptom of the bigger picture here.
Let us say he was stick thin but refused to wash, would this be ok?
He seems to think he can settle in to a life of the couch potato, and that is fine, except he is married and OP may want more from life now and in the future.
A friend of mine has recently gone to a personal trainer in her late 40s lost lots of weight and is now a size 6/8, she wants her husband with her on their future adventures, but he had similarly given up. She booked in the personal trainer and gave him the hard truth, he has been going because it is costing him 270 a month whether he goes or not. They either work together or they ultimately separate.
I am overweight, but I am single and have my reasons which really aren't relevant.
It is your marriage and it sounds like time to put the writing on the wall in giant letters and give him the choice to join you or ultimately get left behind.