I’d say do what you feel is right and if you feel moving far away, then do so. You are the sound person who is looking for your daughter. You have given your wife chance after chance and she can’t manage her gambling, her reasons are hers. Yet, your daughter should be given the best shot to live a normal life, not one controlled by the addiction, having to make sacrifices in order to bail her mother out, debts that certainly will have an affect on her. I think it is wise to separate this debt from you, so you won’t be responsible.
Of course this is extremely tough on you, but never feel like you are breaking the family, or taking your daughter away from her mother because guilt and others will tell you to work on it more. Of course, it will be up to you, but if it were me I’d make sure to get my daughter out of harms way.
About four years ago, I stopped my daughters from seeing their grandfather, they were 8 and 3. As I was estranged from him, after numerous interventions yet he kept gambling. My point is my youngest doesn’t remember the crazy things he said and did to upset me. However, my now 12 year old, the older daughter, still remembers what I went through.
Take it easy, this won’t settle over night or even a month. It will take time for you, but do how you feel and if someone tries to pressure you to forgive your wife or gives you the spill how staying together is the best thing for your daughter, they haven’t live with an addiction as cruel and manipulative as gambling. It’s an addiction but doesn’t erase any of their actions and it should never be used as an excuse or crutch. Life is full of rules and consequences.