Have you ever thought about getting some "toys"? Trying to have a clitoris orgasm? That's what i have to do. I've never had an orgasm with just sex alone i need that extra stimulation.
And with the toys when you don't have your partner around you don't have to worry about it. And it might be safer than being with multiple partners.
I go through phases like that too, I've been with my fience for 10 years and there r times i can go months without even thinking about it, and times where he can't keep up. It might be hormones, im not sure. But if your worried about it i would see a doc.
Best of luck to you :-)