Is he just not into me anymore?

My fiancé and I have been together two years. The past month our sex life has decreased drastically. The past two weeks we have barely kissed. I have questioned him as to why we don't have sex and he just says, when I'm in the mood your not, and when you are I'm not. So finally! Yesterday we started to make love and it felt like he was not completely erect. Then after about 3 minutes he decided that he didn't want to he wanted a bj. Is not attracted to me? Is it something else? Is this normal?

There can be many causes to lost libido.

Are there any new stressors in his life? What about illness? Any new medications? Have the two of you been fighting recently? Is he satisfied with your relationship? Has he been overdoing it with porn?