Taking too long to cum

I despise my bf eating me out, not that he does anything wrong (he could use a class or two on how to properly do it) but it takes me SO long to get to climax, near 10 minutes. I feel like he just gets tired half way through and I feel bad that I’m taking so long so I rarely let him do it. I just don’t understand why other girls have an orgasm as soon as they’re touched and I can only have a quick one with my vibrator.