How to be more easily aroused?

Hello,

I'm a very healthy, active, athletic 31 year old. I have no problem getting and maintaining an erection with or without a partner, and my sex drive is still high if I utilize it. I ejaculate at least every other day or so.

The problem is that I have trouble with motivation. I always have to try to become aroused and maintain it, and take the initiative to masturbate or have sex (which I do) instead of the arousal feeling like it is happening naturally. Is there a way to help me become more naturally aroused, instead of having to purposefully turn it on and work for it? I have worked with psychologists before but it hasn't helped much. If I don't masturbate for a week or more, the urges sometimes come naturally, but I don't want to have to wait like that.