This isn't acceptable. Me and my husband are both huge gamers - we play together and apart. But in normal times we also go out for dinner, go to watch live music, or to the cinema. I hate walks and have mobility issues, so we don't really hike or go out for a wander in the evening, but we do swim and other things.
There has to be a balance to any hobby or it ends up like this really, whether it is gaming, cycling, running or knitting. If that is all someone does then anyone living with them is eventually going to get fed up. They are going to feel isolated and not a priority. Yes you can do things by yourself, but there comes a point when you also start to feel lonely. In this case it also models bad habits for your children.
I can see what will happen if this continues. You will eventually hit your breaking point, divorce him and then your sons, being old enough by that point, will both choose to stay with him and this will be their life. They are still young enough to break this habit and find enjoyment in other things. But this is going to involve breaking the pattern, ignoring your whining husband and taking the boys out to do something else. Frankly, walks and similar bore most children, so it is better to work exercise into something enjoyable e.g. going to the zoo or whatever you have locally.
But, you know that you won't get any support from your husband. Frankly, what is he even bringing to your life at the moment, except making it more difficult. I think you have a hard decision to make here and a conversation about what needs to happen to stay married.