It sounds like you're describing having a responsive sex drive. That's usually attributed more to women, but is still completely normal for guys from what I've read. My GF is the same in that she can get in the mood from attention, but the desire doesn't come to her often out of nowhere.

I come from the spontaneous sex drive side, so it's hard to imagine not being in the mood or not having these thoughts come up all the time. I go to porn because my mind craves the sexual energy. Sometimes I'll watch or read it without masturbating because the feeling of arousal and mental stimulation is so enjoyable.

I like and accept who I am, but honestly if I take a step back and look at things objectively, would I recommend having a high sex drive? Probably not. When you see random people walking down the street you check them out. When you get introduced to a coworker's friend you immediately think of fucking them and try to keep your eyes off their tits the whole night. You know people are more than objects, but your caveman brain is still there telling you otherwise. It's kind of a biological curse, but it can be a lot of fun. If you're happy with what you have then that's probably fine.