What are my chances?

Honestly, I would love to have a child right now. It's all I've ever wanted. However, there's a slight stipulation. So my boyfriend and I often have sex and we've never used protection. We recently had a pregnancy scare. Not really a scare. But ya know, we thought that we were gonna be parents soon due to an accident. It was the first time he ever came inside of me and it wasn't on purpose. He normally pulls out. I was just wondering if he continues to pull out, what are my chances of actually getting pregnant? And if we have sex during my ovulation window on the day with the highest chance of pregnancy, and he still pulls out, what are my chances??? Please answer soon ladies! Thanks :)