Guys, how do you learn how to control yourself when it comes to sex?

I'm seeing a main girl rn, but I ended up sleeping with someone else. With the other girl, I went in completely raw on the first date. I didn't cum inside her thankfully, but now I'm worried about spreading anything to the main. I'm sure I'll be fine but still.

I used to have the worry that my dick wouldn't go up b/c I had death grip, so I would avoid using condoms bc of performance anxiety. Nowadays I'm starting to get some career success, and people will start noticing. How do you guys get yourself to have safer sex?