No, I certainly don't think a submissive fantasy is gay. Nor do I think a submissive fantasy is freakish. I think your H has fantasies he is afraid to share. Being dominated is a VERY common hetero fantasy of males, and one which they are loathe to share if they fear someone might be judgmental of it.
Well, I think he actually has said (in a round about way) he would like me to take charge sometimes and just jump on top of him, so... Come to think of it, I was probably the sexual aggressor when we first started dating. My first mistake of many...
