I dated a guy who was fine boned... he was ALWAYS 20 lbs lighter than me. Beside him I felt like an ogre! I think a man should have broad shoulders and some fat... if he is all muscle (my ex husband at the end of our marriage) there is nothing to hold on to. Or very thin there is not much to feel.
On the other hand he should be healthy.... I won't date a guy who is obese as I then have thoughts that he will have a heart attack... one guy I dated was 100lb over weight... carried mostly in his upper body... and he had horrific sleep apnea because of it. I didn't know which was more upsetting when he snored and stopped breathing or when he had on his machine and I couldn't hear him breathing.