Boyfriend came inside me...

Okay so my boyfriend and I never use condoms. Our entire two year relationship, he has been very good at pulling out. Not one mistake. Except, this time. I'm not really so sure it was a mistake because he just said "i love you" and then got off of me. Like I wasn't even aware he was done? Then he just sat on the edge of the bed. He didn't even say anything about it. I just ovulated last week so there is a very slim chance that I could be pregnant, but there is always a possibility I guess. Do y'all think I should get plan B?