Surveys: He says "I love you" back to me in person, but never any time else, why?

I said "I love you" first and he replied "I love you too" (after 3-4 months of on/off dating and even a couple snags in the "relationship") anyway it has made me quite flakey that he cannot text back or end a phone convo with "I love you". I mean what? Is he waiting for me to say it first again? And he's ignoring me now (on vacay this week until Fri--roughing it in a canoe in canada) because I texted him to "just forget it." and accused him of seeing some other female.