Always scared

I have thick, creamy white discharge for the last half of my cycle every single month. I see it in my panties when I go to the restroom, I see it on my SO when we have sex. It doesn't itch or smell at all. There's just a lot and it's sometimes embarrassing. I get tested for chlamydia and gonerrhea every year since 2013, and each year they come back negative. My SO and I are completely faithful to each other. I take good care cleaning down there and making sure it's dry to prevent yeast infections.  
I guess I'm wondering what it could be and if I can decrease it. I've heard that it's normal...I've also heard that it may be yeast anyway, which is normal. I'm just looking for input.