Ejaculation Delay

my boyfriend and i had sex + oral last night for the first time. i was giving him head for at least 20 mins. i know my head game isn’t weak, so i asked him why he hadn’t came yet. he told me it was usual for him not to cum or take up to 2 hours to cum and he didn’t think he would cum that night. i was so shocked and surprised! we had sex for at least 2 hours and he still didn’t cum! he assured me it’s always like this and not to feel insecure about it. but i do. i feel like its me, not him. i even asked if it was because he had recently jacked off that day or something, and he said he hadn’t came in 5 days. so i’m just confused & i want to please him & make him cum. i just dont know if i can keep going for 3+ hours.