In your boyfriend's situation, he may clam up a bit because...well because he's a man. They are supposed to be the ones who stay strong for us right? Let me be perfectly clear...I do not believe in that stereotype, but I know my husband feels that way..
I guess I will just be there for him even though it is me getting in touch - I just don't want him to think I'm bugging him.
I know that he feels so down and probably worthless.
I just hope he goes back to the way he was after surgery because he is a great guy and funny, vibrant, etc.
I think Mom2Izzy brings up a very likely possibility, and as a guy, I'm not at all offended by the stereotype either. None of us obviously know the inner workings of your relationship, Carolyn, but no matter how much perspective your boyfriend may or may not have yet on this drastic change to his life, it takes time for even the most well-adjusted people to accept and adapt to the new normal.
I joked in a thread a day or two ago how I didn't tell my wife, pregnant at the time, about my need for surgery until after it was already over. It was just a joke, but truth be told, if I'd been hit with the same news earlier in our relationship, prior to marriage, I might have had a somewhat similar reaction as your boyfriend. Perhaps he's simply trying to shield you. Perhaps he doesn't want you to be around him in a weakened state. Perhaps he's having a hard time accepting that he has no control over the situtation and will need more help from those around him than he ever could imagine. Perhaps he realizes that he needs you even more now, more than he thinks you need him. Who knows for sure, certainly not me. I can tell you a few things about heart valves, but certainly not what to expect in terms of male behavior!
In any case, he is obviously lucky to have you in his life, and hopefully he will overcome this sooner rather than later. He might not be open to your encouragement right now, but that doesn't mean he doesn't need it.
Now, just so you know, I feel completely ill at ease offering these opinions, I'm not all equipped to advise on personal relationships! By the way, I noticed that your first post said that he is "only 36". I felt the exact same way at 35. Little did I know at the time how many face this in their twenties, teens, or as a child. I had open heart surgery at 35, and looking back, I consider myself very lucky. My daily life is no different now than it was before. Everything I was capable of before, I can still do now. So, your boyfriend should be just fine. He may not fully realize it right now, but this whole experience may actually make him even "stronger". Best wishes!