Welcome to 3FC
Getting support from home can be difficult at times. My personal advice (and keep in mind that I've vowed to be single forever, lol) is that you should consider this a personal project and not worry if he doesn't seem supportive right now. Plan your meals and exercise anyway, and if he does disagree for any reason, just gently remind him that he said anything was fine
Otherwise, don't seek his opinion, just do what you think is best for your health, and only consult him if it's something that directly involves him (such as when you need his help carrying in a new treadmill, lol). When you start to lose the weight, he'll sit up and notice, and I think he'll become more supportive then.
I'm very successful at staying happily single
But we do have a lot of women here that have significant others, and I'm sure you'll get more, and perhaps better advice.
Whatever you do, don't give up. Don't put your wishes to be healthier and more confident aside. Love yourself first