selfish bf

how do you get boys to go down on you? because my ex never did and told me "cum is nasty" but expected me to swallow when i gave him head. my friends have boys who give them head but literally no boy i have ever been with has ever given me head and i don't know why. it's not like I don't take care of myself either because im always smooth and clean before anything sexual and nothing smells so im just confused, is there like a convo im missing or?