Hmm, tough one. Marriage is what you make it ultimately.
There are a couple of key necessities. Compromise, trust, love, respect.
Your current marriage sounds more like a free loading kid and his Mom. Sorry but there it is.
What's he providing for you? he is living rent free , pays for nothing and plays computer games. Gets away with it all because he says he loves you.
If he was an ignorant ***, would you even ask if this was ok.
He should be providing for you as his partner,since he chose to be with you.

He has a responsibility to you too, to your happiness and well being. We only have one life.
I can't speak as to the situation with your ex, except that if something is missing where you are, you will be drawn to the fantasy.
Do you want to spend the rest of your days with a guy you despise sleeping with? Probably not.
The question was is there more? The answer is HELL YEAH!!
Why isn't he working and taking you out? You don't have kids, you should be taking road trips, traveling the country.
Who pays for his dogs?
The insurance?
The food?
The utilities?
I am gonna take a guess that it's you. Your "husband" has it made.
I don't know if it's the same where you are but a marriage can be annulled if un-consummated,in some places.
Just a thought.
Really though it comes down to you. If your content being his mother instead of his wife. Carry on.

Personally I think you want more. All the best. Take care with yourself.