Inexperienced and frustrated

So I've dated this guy for 6 months now and to be honest, I liked him a lot and things are going great between us. But we're getting more intimate, and it is very intimidating for me because I'm don't have much experience with sex (read: Virgin) but he's not. The fact that he's willing to wait because I'm not ready to go all the way is one of the main reasons I stayed with him.

Last Monday was his birthday so I decided to surprise him and tried to give him oral and he's very pleased when I said that. But I can't finish him and it's very awkward and I feel so useless. He finished himself off and said to me gently that it's okay and he doesn't expect me to be good the first time. But he does seemed quite frustrated.

I started reading and googling stuffs from the internet but everything is very confusing. I tried doing that again the next day, this time equipped with 'knowledge', still I can't make him. I cried and he just hugs me without saying anything.

I'm afraid that he got tired of waiting and finds other outlet to vent his frustration. What should I do? I'm not ready to give up my virginity but I don't want to lose him either and the whole point of oral is to make the wait bearable for him but now I'm unsure of everything