Is there something "wrong" when after living with boyfriend for 4 months, we no longer sleep together?

My significant other and I have been living together for 4 months. We are not kids, both previously married. Now, after the 4 months, we don't sleep together, sex happens when he wants it ( my advances are met with resistance) and he no longer says " I love you" or tells me anything more than " Your hair looks great". What do you think? Am I being overly sensitive? Any way to resolve?