Pregnant and husband found that I was taking nicotine

I tried to stop, ill go a few days without it ans then I will be back at it again knowing how deterimental it is to my unborn baby that I don't use nicotine. He said I was a bad mother, that I didn't deserve to be one, he also said that I was poisoning his baby and he would resent me for life if anything is wrong when the baby is born. I feel so depressed, I love my baby I have waited so long to see him, I just have it hard controlling myself..and I loathe myself for it...I feel like a mountain is weighing on my heart.