I don't know... (it was Pirate's post that prompted this post)... If someone in a relationship can't say they love the one they're with, it sort of tells me there's something wrong...
I mean, sometimes people don't say things in words but you can tell in everything they do, so sometimes words aren't needed. There are other ways to say "I love you" than in words. So I can understand this...
BUT, this doesn't sound like the case here... it sounds like he doesn't know if he loves her or not... and that is why she feels "insecure."
I mean sometimes people are in different places in life and it becomes a matter of how long can you freeze yourself and your own progression waiting for them to meet you where you are? And if you do, will it even matter? Will all the time and suffering spent waiting even be worth it? Sometimes there are moments where a path needs to be chosen and a decision needs to be made... well, except how one feels usually isn't a decision.
Anyway, I agree that talking about it is the way to go. I don't know what else though.
ETA: I could see myself not saying "I love you" at first but I would always be trying to express it. I don't seem to say that right away. But if I was being that way and the other person asked I'd probably get this shy look on my face and try to say how I felt. It might be hard, but I would be trying. But I have issues.
Once I was confident the words wouldn't do the relationship in then I would feel much better.