Help me!

Background: I'm 21, recently out. I've been hooking up with an older guy, MUCH older guy and I have a hard time saying no to bareback. I don't think we're exclusive and I have some intimacy issues and am clearly to scared to talk about it. Everytime we hookup I spend like two or three days scared I just contracted a disease for being wreckless. I need tips for being a self-secure gay man. I'll take the negativity if someone can at least offer SOME constructive criticism. -A