the only thing he said was "I need you to lose the weight"

I don't think he's being a jerk by saying this. It's straightforward. It's not like he insulted you. Being larger than you used to be is simply a fact. He cannot help it if he is not attracted to larger body types. We do not even have to bring good/bad into this. There are people on all sides of the "fat acceptance" debate, and we could argue on this all damn day. The outcome will not change the fact that the person you love is not attracted to your new body and flat out told you that he needs you to lose weight. You cannot change a man. So even if you assign some sort of morality to this situation, it doesn't actually change anything.

Fact: you've gained weight Fact: your significant other needs you to lose it.

What you do next is your decision. The power is in your hands. Maybe he will not leave you if you stay at your current weight. But what if losing weight would improve the quality of your relationship? What if you could be more emotionally intimate and close with him if you lost weight? Is that not worth exploring, breakup or no breakup?

I stopped going to the gym, gained quiet a bit of weight, stopped taking care of myself over all - I believe this is mainly due to the fact that I have been in and out of depression a lot the past couple years

For what it's worth, I think this is a lot bigger than your weight for your boyfriend. How would you like to meet a vibrant, energetic, whole person only to have them stop taking care of themselves and become a shell of who they once were? It can be exhausting to be with a depressed person - often they won't tell you this, because you probably already feel guilty for being depressed and they don't want to make you feel bad. But it's true. Like any other illness, it can be difficult for the family and supporting people in the sick person's life. I doubt that losing weight is the beginning and end of his troubles. He probably wants you to be more confident, to care for yourself in other ways like hygiene and beauty, to be more active outside of the house or to be able to keep up with him. It's not totally a superficial thing for him, I can promise that.

Being fat doesn't make you a bad person and it doesn't make you unworthy of love, by the way. It's just a fact: you're fat. Take a deep breath and an honest look at yourself in the mirror. Realize that you are entirely in control of what happens next. You could lose weight, and I think that would probably make you feel good and improve your relationship. And there are people who are fat and love it, and find partners who love their larger bodies. That's also an option, and if that's what you really want and what would make you happy, then cool. You're in control. The only thing I'd hate to see you do is continue living a half-life, not being true to yourself and not pursuing the things that would make you into the person you want to be. We feel our best when we are living our best lives and being true to ourselves. You're not doing that right now. Your boyfriend also deserves to know how you intend to live your life and what your goals are. If you don't want to lose weight, cool - tell your boyfriend this so that he can decide what is best for himself.