How to tell him

Michelle
This is my second pregnancy. I just got back with my daughter's father and we are working on us. 
I was taking birth control pills and we had unprotected sex a few times. So now I was feeling sick found out I had strep began taking antibiotics and once I finished I was was still feeling sick to my stomach. I also have PCOS so I believe I mistaked a cyst rupture for a period and I'm pregnant and unprepared. 
I'm afraid to tell him because he has four children including our daughter so he may not want this baby. 
Any advice?