Mild worry

So on sunday, me and my boyfriend had quick unprotected sex. He pulled out and came about 30 seconds after pulling out and his precum was clean seeing as he came friday morning, showered and promptly of course peed throughout the day. Im not worried worried but im just curious. Another issue is according to eve i was on my fertile window. What do you think the chance is? We both made sure that he pulled out before he came so we should be safe right?