Boyfriend surprised me with sex...but stopped?

Last night I wanted sex so badly (as always), but my bf was just not in the mood. He said soon & that since my bday is on Monday we are definitely doing it that day. I've been with him for over 3 years now & we pretty much do it every 3 days. We went to bed last night & all of a sudden I feel him feeling me up. I'm like half asleep & so is he but we start doing it (always hot when he wakes me up for sex). After like 3 mins of doing it, he just stops without finishing. I asked him why & he told me he just wanted a quickie & that it happens sometimes. Also that he was only a little horny & half way in the mood, but that most likely means we'll do it soon. He was trying to say it's like teasing but actually starting to do it. This has happened before & tbh it makes me feel bad. Like I wasn't good enough or it didn't feel good. He told me it did. Like does this happen ??? I have no idea.