How can I prevent tearing from sex

I had sex with my boyfriend for the first time like two weeks ago and ended up with a kidney infection from a uti caused by latex. It took me about two weeks to recover to be able to feel safe enough to have sex and the first time we did it since then was on Thursday and I had to stop midway because i could feel the opening of my vagina start to sting and really hurt. Giving that my boyfriend is blessed 🙌🏼 clearly lol. I've never had this problem in the past even with exes who were well endowed themselves. I've tried looking it up and everything says something about lube but I know that's not it because I'll leave puddles. We even tried without a condom because of my sensitivity and it still does it to where I bleed a little. What can I do to prevent this? Will I just eventually fit him better? And could this be because he is uncircumcised? Plz help I just want to be able to have sex with my boyfriend