I need motivation.

I hate my body and I need to do something about it but I just cant find the motivation. I have 2 children aged 2 and 1 and a fiance who is a dickhead at the moment so things at home are hard. I really want to do something for my self but I keep finding myself eating what I know i should and I know it everytime im eating it or drinking it but I dont stop. I feel like shut when I've eaten it but I eat it anyway. I don't know how to change my mindset. Can any of you help?