A family with a history of addiction ... and me

[Bluffoon]

I don't think you need to justify your behaviour to these people. I would point out to your wife that you are a responsible husband and father and let her know that you are not all that concerned about her families opinion of your "gambling problem" and that you will not make an issue this time of their misguided judgements.

I would also keep an eye on these people. They sound like troublemakers to me. It sounds to me like they are trying to interfere and or control you and your relationship with your wife. Big red flag.