I remember hearing at my grandfather's funeral during the eulogy that my uncle had never in his some 50+ years been told by his father that he loved him. Apparently, he told my dad ONCE that he loved him.
I personally think never hearing that was one of the most damaging things in their lives.
There are easily women that don't need to hear I love you... I suspect they are hurting somehow. They probably wouldn't know what to do with those words. And it makes me wonder what they offer their loved ones.
For example, a man that can't say I love you... Has he ever heard it himself? From his mother? His father? Does he even know what love looks like. Will he be able to teach his sons to love. His daughters to accept love?
There is only one man in my life that can look into my eyes, say I love you and make me melt. JUST ONE. My male friends can say "love you", and I know it means they care. My family, men and women say love you, before we hang up on the phone... we care. my Best friend and i sign off with I love you's in e-mails and letters... well, we're best friends, she has rank next to DH;) DH's best friend always rings off with a Love you guys!
If he never said I love you... there would be a hole in my heart. If he died on the way to work, and we didn't say I love you to each just before, I'd be sick over it. Yes, some women need this. But only if and when it's real. I couldn't care less about an I love you from any other man.
And so perhaps you can't pull yourself to say it... because you don't mean it. And that's fine. It should be genuinely true!