You have to decide how important those words are for you. My mom and dad have been together for thirty years, she says he's only said it a few times, but my mother, being the titanium-plated being she is, says it doesn't bother her because she just knows. And she seems to be right. I mean, they're still together after all this time and it seems to be going well.

I, however, am more like you. I need frequent confirmations. At least more frequent than once a year. Perhaps he has trouble just saying those words, because he's afraid love makes him weak even though he feels it? Men are kinda weird.

If it IS really important to you to hear those words, I would ask him during a neutral evening (not during a fight and not at a fancy restaurant).
"I just wondered... Is there a reason why you didn't say you loved me back?"
You might not like the answer, but if you're like me, you'd rather know that not know.

If you decided you have the patience to see where this is going without knowing whether or not he loves you, I advise that you just hold your tongue and swallow the doubt.

(English is not my native language, but I trust you catch my drift)