Need advice!!! Please no judgements!!

I am 22 and I weigh a little over 200. I have been trying to lose weight but every time I go on a diet and start an exercise routine, I quit within a few days. I have been with my boyfriend for 3 years and have gained this weight within the last year. I am very depressed with how I look. My boyfriend says I'm still beautiful but a lot of times it feels like he's not interested in me at all. Please help me!!! I don't know what's wrong with me and why I can't find the motivation to lose this weight!! I want to look and feel beautiful again!!!