I seriously need dating advice please help :(

I’m so new to dating and I’m 18! I’m ready to actually be with someone. I found the sweetest guy I’ve ever talked to makes me feel so happy when I’m with him. When I’m not with him i just fear he’s with another girl. Even tho we aren’t dating we have discussed we were exclusive until he pops the question WHICH he has been hinting about asking me this weekend(another story) i dont know what i should do i am falling for him but i don’t trust him...he just hides his phone and i have never seen who he talks to and he looks at my phone every time I’m with him, im to scared to confront him bc i don’t wanna sound crazy or needy or scare him away i want him to think i trust him... but because i have anxiety and i don’t trust anyone and I’m not sure if i will ever trust anyone and that scares me because, i don’t want to be alone. Could use some great advice. Should i say yes when he asks me then ask when we are bf gf to see his phone or.. i dont know This sounds like middle school shit but I seriously need some A1 advice about this