I know mine knows. I had only been seeing her for 3 months when she had to cancel our session due to a family emergency. She said: "I know you're not going to like this..." She has said and done other things that also shows she knows. Though with me, she'd have to be completely oblivious if she didn't know. We talk about my fear of losing her almost every other week. That plus all my emails and me verbally admitting that I'm attached...

Though I have had a few past Ts who didn't get it. Probably why those Ts never worked out.

When you seem him again, ask him. Or like Hooligan mentioned, give him a compliment. Or even as for reassurance.

I know it can be difficult when they miss sessions. I dread it every time mine has to miss.