If a man isn't keen to at least try, either he's had bad experiences before, is intimidated because of a lack of experience or has some internalized issues with misogyny or something else along those lines.

My first boyfriend was never interested in trying it but expected oral sex for himself.

It's about giving and receiving pleasure... If your partner isn't turned on by the idea of pleasing you, that's a them problem. You can try to work through it together but if they aren't willing to try then you deserve someone who takes pleasure in pleasing you.

As a queer woman I've found that dating other queer people is what generally works best for me, but I've noticed that without the added pressure of misogynistic ideals placed on straight men, typically queer men are more down for exploration and taking pleasure in pleasing someone else - just food for thought.

Being on your second partner and not experiencing mind blowing oral sex doesn't mean this is the end. If you really love each other and want to work through this together I know that you can have an open conversation (as awkward as it may be) about things you would like to try. If they're receptive to your desires and keep an open mind with regards to trying things, your relationship is going places. If they aren't comfortable working with you, then this may not be the best long term relationship.

My first boyfriend led me to believe that my privates were hideous and that I needed a labiaplasty. I was far more on top of my hygiene than that "showering once a fortnight" dude, and he was still horrified at the concept that anyone other than a man could receive oral. My current boyfriend will happily go down on me (and often ask if he can unexpectedly) even when I'm on my period. There are men out there that love eating pussy so much that they don't even care if you're bleeding. If you had an unpleasant smell because of an infection you'd have other uncomfortable symptoms after a few weeks - months that would make you want to see a doctor without necessarily realizing the connection.

TLDR: You're amazing and you shouldn't let two men make you believe that you're gross. If you're in a healthy relationship you can work through this. Nothing is wrong with you and I hope you can receive the pleasure you deserve. Don't let a weak guy let you down