There might be 'a lot of love' between you but love is not enough when there is addiction in the relationship. He clearly doesn't want to change (as his behaviours reflect), so your choices are pretty clear: stay with him knowing he is happy as things are or or set firm boundaries and remove yourself from the situation. If neither of you makes a change, this is your life for the foreseeable. As you can't make him change, the change has to come from you.

IF you want to know why you are like this, that is something you can explore in counselling. No one here could answer that question for you. At the end of the day, there needs to be action, rather than not doing anything or wishing/hoping for things to (magically) be different.