Lose weight or I'll dip he said

So I got back with the ex, things are going alright, we're both on our own journeys of getting the right life we want, I need to move house, closer to my family, I need a new job whatever right.
I been unhappy with my weight for awhile, 80% of my wardrobe doesn't fit anymore, I miss my clothes, I miss the confidence I had when I slimmer, the whole thing.
My boyfriend sat me down and just told me "you need to lose weight, I'm not attracted to big girls, I met you curvy, you were like 160lbs, then you were looking amazing when u lost more weight, now you need to lose weight"

Part of me is really pissed off with him, how dare he tell me about my weight, but I know he's straightforward like that and he's the one that has to look at it too, my mum always said, don't make a man tell you twice, he's very fit and asked me if I would still be attracted to him if he was 300lbs, unfit, not active, poor stamina and I went quiet 😂
I get that, losing weight is something I want, but to be given an ultimatum by my man is kinda harsh.