I need some advice! Subject: Oral

So I'm in a year long relationship, and at the beggining he would pay alot of attention to me getting to climax as well as him, most of the time he would eat me out and use his fingers to make me orgasm before we had sex.  Ive always given him what he wants in oral and hes always said he loves my blowjobs. Lately however hes been sort of selfish and I'll give him a blowjob literally for more than an hour, sometimes my jaw gets so tired it bothers me, and I'll let him know and he just sort of asks me to keep going, but when it comes to me most of the times he'll only eat me out if I ask for it and when it happens its just mediocre, and for like 10 minutes which by then he just switches to his hands. I have been vocal about me wanting him to reciprocate better. But it's just not happening. Could it be that my vagina has changed flavors and he doesnt like it, or anything else that could have changed or is he just selfish and lazy?