Can someone answer this?

(My last pregnancy) my SO admitted to me that 3 of his exes have been pregnant by him. 2 of them had miscarriages and one had a stillbirth at almost 30 weeks pregnant. I never knew this. I went on to have a healthy pregnancy and good delivery but, We found out we’re pregnant again and now i’m nervous.....being that all 3 girls lost their babies do you think he (his sperm) can be the problem? that makes me nervous