Help! Pregnancy crisis

I just found out that I'm pregnant. I'd be about 4-5wks. I really don't know how to tell my DF though...

Abit of back story-

I have 2 kids. DD is 6, DS is 16m. The day before DS was born my DFs company was forced into liquidation and his other business he started is still in the beginning stages and isn't making much money atm so money for us has been really tight. We struggle every week with having enough to survive till payday. I fell pregnant again in may and had to terminate, mainly because I'd just been diagnosed with cervical cancer and my treatment couldn't wait till after I'd had the baby but also partly because of our finances. I had a mirena put in at the same time but I had alot of issues with it so needed it taken out. We tried being really careful about not having sex during my fertile window unprotected. I was using opks and using condoms from afew days before my surge till afew days after. On one occasion though in the heat of the moment we forgot. It turns out it only took that one time and I'm now pregnant again. I told DF how much I regret having the termination and that I would love another baby but accepted his stance on it, being that we couldn't afford another and his worries about my health. He said we could reassess in the new year and if we were financially better we could start trying. I was ok with that. The hospital told me after the procedure to remove the cancer that falling pregnant again would be very risky because they had to remove most of my cervix so most likely I wouldn't be able to maintain the pregnancy which could put my life in danger. I cannot have another termination though, that I am sure of, but now I just don't know how I'm going to break the news to my DF about the pregnancy and that I will be keeping it this time. I know there is risks but emotionally I cannot go through it again. I really need some advice on this...