Random but very curious

So this is tmi but my husband and I have sex often and sometimes he just prefers to pull out and bust other places. Well I wasn't tracking with ov tests this month I usually wait for the cramping and CM but he started to pull out but some got in there (we are TTC so no big deal) but I realized I had fertile CM my cervix was very high soft and open and I took a test and it was positive for ov the next morning. I was so bummed that we missed it Like I should have tested so we could have done it right. But anyway what do you think the chance are of being pregnant with only getting partial during that time?