My husband did the same thing "saying NO if I suggested it" in the first few years of our life together. Every time I asked or initiated it was an automatic NO! This killed me because I felt undesirable and would try harder. So then I stopped trying and he started asking/initiating and we would have sex. But as soon as I asked I would still get a NO. Well, now I initiate but in an odd way and it has worked for us. He will come home and I will say I don't want sex today so please just leave me alone. Like a child with reverse psychology, over he would come kissing my neck and so on. Now after being married for almost 10 years I have told him what I do to get it when I want it and he laughs and says he has always known.
I still feel it was/is a power trip for him. I say whatever works. Good Luck figuring out what will work for the two of you.
-Summer