My man doesn't give an equal share. HELP.

Me and my boyfriend have been having sex for about 4 months and I give him everything he wants, blowjobs whenever, pictures whenever, sex whenever we can, ect, but when I ask for things in return, him going down on me, he makes it a big deal and never does it, I'm clean down there, I wouldn find anything to be unsanitary, help / opinions please!