More advice needed: How can I fix a friendship, or is it beyond repair?

This is in relation to another question of mine. Please first refer to Advice needed: How can I fix a friendship, or is it beyond repair? for background.

I have been trying to limit my comments and to be less 'enthusiastic'. I think I've been successful enough with this. However, this hasn't helped much, I'm afraid. At first I thought that it did, but as time went by he still seemed to act as weird as he had been. He seems fine in e-mails . . . even his old nice and quirky self. But face-to-face interactions are still strained in most cases.

I know I'm going on and on . . . sorry . . . I'm trying to get this off my chest by writing about it and asking advice . . . more constructive than sulking about it I guess.

As an example: We have a bit of a standing coffee session (to which he had invited me) at the beginning of the day where a few friends (whom he had introduced me to and who have also extended the invitation) just sit and chat and drink coffee and laugh about stuff. In the past he used to let me know when he goes to the coffee session, because it is not always at a set time, and does not necessarily always take place. I don't always see when he leaves, and he has been leaving without letting me know a few times now. I just discover that he's gone, and assume that he must have left for the coffee. This should be OK, since I suppose one just goes there at around the same time and sees whether any of the others are there. But I sit a few seats from him in direct line of sight and within earshot. I know he usually goes to get one of the other friends who sits quite a bit away from us. A quick tap on the shoulder to let me know he's on his way would do, but it feels as though he is being deliberate in not letting me know. Maybe he feels that I am intruding into his space with his friends, but he invited me after all. I've been thinking that it is probably not deliberate, but it just seems too obvious. The friends are all a very nice bunch and I know that they like me.

I feel extremely childish to feel this way about such silly things, but of course this is not the only thing that bothers me . . . but the little things usually do bother one quite a bit, don't they? In fact, his way of handling things seems very childish as well.

What disturbs me the most is that he is so nice in e-mails (and when he needs something from me), but, for example, when he just greets me in the mornings his reactions seem strangely awkward and forced.

I dunno anymore. I suppose I should let it go, but we need to work together, as I said, and I hate feeling this way around him. I hate the idea that he needs to strain to seem civil or friendly towards me. He's not outright rude, but I hate the awkwardness and the way he seems to not 'listen' to me anymore . . . meaning he would read e-mail while I am talking to him and doesn't really hear what I am saying. I wish it could be natural again. It's so frustrating.

I know it seems as though my life revolves around him . . . it's just that I hate friendships going this way. I can't remember it ever really going like this in the past with any of my other friendships, so I feel really awful.