Liquidy cum

Not sure how else to put this but I’m on the nexplanon and today was the first time my boyfriend ever came in me. I’m not scared, I know this is super protective and even though there’s a small chance I could be pregnant, I’m still not worried but I have a question. Anyway, I never ever see my boyfriends cum. I always swallow and I’ve never seen it. Well today when he came in me, I was riding and after I hopped off. I felt it stream down my leg but there was no white colored substance. I don’t squirt or I never have and I’m pretty sure I didn’t cum, I didn’t have the release. Anyway I was just wondering, what causes a guys semen to be clear and I’m sorry if this is a stupid question but in that clear semen, is there still sperm? I always assumed in white semen, the sperm was visible making it white but I’m not very educated on clear, super liquidy semen. Thank you in advance.