self conscious about the weight I've gained...

So when I met my boyfriend, I weighted about 140. It's been 2 years now, and a lot of mental health issues for me (my mess made me gain weight, along with depression in general/not caring), and now I weight 204. I'm trying desperately to lose weight, but I'm still SO self conscious. I don't initiate sex, and he's afraid to initiate it because I deny him all the time because of my insecurities...... we're struggling in our physical relationship and I don't know what to do. I'm eating healthier/ 1200 calories a day, and exercising 2-3 times a week. But how do I gain the confidence back??! I was hot and skinny and now I'm overweight (and it's like very obvious) and self conscious 😔😔😔