What did you expect him to say though? I expect he either a) feels awful. Bad, guilty, ashamed and doesnt know what to say. (Whenever I phrase things that way to my bf, he just stares at me, wordless. When I ask why he doesnt say anything, he says, because I feel so bad and guilty, what can I say?) or.. b) he's in a meeting and hasnt seen/can't respond to it yet?
What if you had messaged him... "I felt a little sad this morning as its 2 years today when you first left, but then I remembered how you came back and how we are rebuilding this and then I felt really blessed...