Vaginal Discharge Smells Like Sperm!?!?!

Tiffany • Im 23, married to a wonderful man, have a beautiful 4 year old daughter, and currently in Mexico. 🇲🇽🇲🇽🇲🇽
Okay, a little information then we'll get down to the itty gritty. 
My last AF was Jan 30, it lasted 3 days. My cycles are very regular. 28 day cycle, 3 days. 
My fertile days were Feb 12- Feb 16. Me and my husband use the pull-out method, he knows his body very well. 
Within the 3 years we've been using the pull-out method, I've taken Plan B 4 times. 
So I've been having symptoms for the past week, nausea, sore breasts, backaches, fatigue, and extremely emotional. I didn't think anything of it. Until yesterday. I was taking a shower and I felt wet so I reached down and came up with white cervical mucous. Okay. I smelt it. Weird I know! It smelt like sperm!? Omg! 
How long does sperm live in a woman's body? How did this happen? And what are my chances that he accidentally came in me around my ovulation date?! 
Any help with his is greatly appreciated! 
We would be extremely happy if I were to be pregnant, we were gonna start in July! We'll be happy either way! We have 1 child already, she's 4 now so another baby would be pure joy and happiness! Thanks a bunch!?