Am I The Only One?

I like to analyze myself, and lately I've been thinking about losing interest too quickly. And when I say that, I mean everything. For example, I start a new job, I'm super enthusiastic for the first few months and then I go into a monotonous mode. I hear a song a few times and then it stops listening to me. Even with the men I'm with, I seem to lose sexual interest within three months. I'm smart enough to know that I can't change my boyfriends in a few months, etc. I've been at my current job for three years, for example, I've been with a friend for two. me, so I generally control this country. But it just keeps me from feeling good. It's as if I need some kind of stimulation and change all the time to feel satisfied. Is this normal or am I the only one