Help! I want to loose weight

I’m super sad. I hate my body so much. I’ve been with my boyfriend for 2 years: and ever since I’ve gained 20 pounds. I hate my body. It is really bad. Like when I’m nude I just look horrible. I have a huge muffin top and no butt so I’m just super unattractive. I hate my boyfriend seeing me naked. I hate being naked. He is sooooo skinny and I just am so insecure. I want to loose the weight I’ve gained and just not be so fat anymore. My biggest problem is having no motivation. No way to start. I eat bad. I don’t know how to stop. I just beat myself up so much and do nothing about it every time I try I don’t stick with it. I’ve given up on myself. Gotten comfortable. Yet I feel ugly every single day. Can’t remember the last time I felt good about myself. Only time I feel good is if I have makeup on or my hair is done. What can I do? How can I do it? Black hair is before