You have always been worth dating.
I hope you never forget that.
Has this guy told you he has an issue with your weight or is that your perception? Some people are genuinely afraid of dating bigger folks (both guys and gals, it goes both ways) or being labeled a "chubby chaser". Society makes us feel like a fetish.
I met my thin, fit partner on a video game when I was 225lbs. We fell for each other before we exchanged pictures and once we finally did, I sent him the "myspace" angles, nipped and tucked a little in photoshop, and hoped when we met he could see past the real, fat me and like me for who he thought I was. I got sick of keeping up the photographical lie and one day sent him a full body photo and said "this is who I am - take me or leave me". 24 hours later he made a 600-mile trip to meet me in person, moved in 8 months later, and we've been together for a total 5 years.
He watched me struggle with an eating addiction that stemmed from my childhood and lose 30lbs, only to put on 100lbs. He's exercised beside me and did crazy diets with me when I felt like thinness was my only way to happiness, and encouraged me to seek therapy to get my mother's aggressive, hateful words out of my head. He attended VSG orientation, held my hand for hours in the hospital bed before surgery, and slept 2 nights beside me in a crappy hospital chair while I recovered.
My point is that there is someone who is thrilled to date you at all stages in your life. The good, bad, fat, thin, poor, wealthy, sick, healthy...and those who think you look amazing when you can't even look in a mirror. There are also those who will threaten to leave when you no longer fit their idea of what someone should look like. Spend your energy on the ones that make you feel good now and forever, not ones who hold stipulations.