I think my boyfriend is losing interest.

I think my boyfriend is ashamed of my weight. He's a big guy and I love him regardless. I feel as though he wish I was fit. I've been struggling to lose weight, I need to lose about 50 pounds. I signed up for the gym but I wish he'd love me for me. I feel like I have to rush and lose so much weight to make him happy. Any tips on weightloss or advice? Btw, i'm so miserable. 😓