Plan B? Or was it me?

a bit of a TMI

So, I just had (really great) sex with my boyfriend. I have the nexplanon implant in my arm & he wore a condom but half way through the sex I felt something drip down there. I asked him if the condom slipped off, but it didn’t. He finished with the condom on (didn’t pull out though) and it was intact and all, but I still had a sticky substance on me, dripping down onto the bed. Was the substance him or me? I didn’t think it was me because it was thick & sticky whereas mine is usually clear and thin.

What do you think? Was it me or should I take a Plan B? Or, even if it might’ve been his, do you think I’ll be fine without a plan B with the nexplanon?

sorry for all the questions. I love my boy, but I’m not ready for a family yet & im a paranoid mofo