When should I tell my BF I’m pregnant

Back story

We currently have a 1.5 year old who is medically complex. She has a genetic disorder that is hereditary and her dad has it also (his is just very mild) our daughter was a complete surprise because he was told he was infertile 18 years ago. She had a rough start and is still on the road to recovery. My boyfriend has been saying he’s gonna get a vasectomy but still hasn’t made an appointment. We are good about tracking my cycle but we slipped up a few weeks ago. I took a plan b but it didn’t work and I just found I’m pregnant. 75% of me doesn’t want to have this baby because

1. I suffered horrible hyperemisis

2. Idk how I could handle being sick and taking care of my medically Complex daughter

3. I don’t want to get fat (judge for me for idc)

4. We just agreed to slip up/take some time off and live apart

The only reason I can think to keep this baby is because there’s a 50/50 chance it won’t have the genetic disorder my daughter has and it may be my only shot at experiencing what it’s like to have a healthy baby. I love my boyfriend very much but I just don’t feel like now is the right time. I just accepted a great job offer after staying home these past 2 years and I don’t want to put my career on hold anymore.

(I’m very pro choice so please don’t come on here mentioning adoption as that’s definitely not happening. If I push a baby out I’m keeping it)

Now to the question; my Bf is under a TON of stress as am I and idk when would be the right time to tell him. Tonight his friend is coming over so I don’t think it’s a good time but I also don’t want him to be mad at me for waiting to tell him. What would y’all suggest?