Throw out all the food. Literally all of it. Get locks or lock boxes for the newer, healthier food you buy. Either meal prep the correct serving sizes or otherwise make sure that there isn't anything FOR you to overeat. You can have treats, but they need to be exactly that- rare and treats. Exercise together, if you can. Cook together too- it'll help you get a better idea of how much food you've been eating, compared to what you should be eating. And see a doctor! There are medical causes for overeating, and there are medications to help with different causes of over eating, including some that help with food addiction.

as someone that dealt with overeating, binge eating disorder & food addiction for a good 4 years (and only recently overcoming it), I honestly would not recommend the whole locking food away or just not having food there. It only made things worse for me being restricted so extremely like that. It could work for some, sure, but there are better ways. Learn portion sizes & slowly work meals & everything down to those correct portion sizes. Mindfulness will be a huge help so read up on it & mindful eating! The other thing that helped me was a journal. When I had the need to eat, I'd have a glass of water & write down everything I was feeling. Even just spending 5 mins focusing on what you feel & recognizing if it's actual hunger or other emotions triggering you, can really help. Then find things that will help you through those feelings instead of food