Was that sperm or lube??

I was having sex with my boyfriend last night and all of a sudden everything down there was really wet-and it wasn't from me. I was on top, and it had to have came out of the condom. I was a little concerned because I'm not sure if he came and then just kept going, and that's what it was? Or if it was just lube that came out of the condom from the top? What are your thoughts!!