Need advice!!

I find my boyfriend very phsyically/sexually attractive, but I get so grossed out by going down on him. His penis tastes/smells standard, and the weird thing is that the first time I ever gave head to a guy (not my boyfriend) I LOVED it, like was really genuinely into it, and I don't know what changed. I think it mostly has to do with his fluids? I've always been really sensitive to consistencies and spunk is kind of... mucus-ey? I prefer swallowing over spitting/having him cum on my body, I just need some girl talk so I can figure out how to get past this and make it more enjoyable for myself. If you've experienced this and have gotten over it please help me out!!!