I don't know that your wife giving you well wishes in necessarily a plea to get back together with you. It would be a bit rude if she didn't recognise the birthday of her children's father.'
Is there any chance that you and your wife would be able to sit down and talk to one another? Without the expectation of you getting back together, but just to let one another know where you are at.
In terms of the website you joined, was it a dating site or a networking site? You have to be pretty resilient to get involved with these sites, as with life, they will definitely show you rejection at times - not everybody can be for you.
I wish that someone had poured cement over your hole under your rock before you climbed back in there. I get that your interests were your wife and family, but why were you interested in them? What did you do with them that was so interesting or enjoyable? I think in relationships we can lose ourselves because we are wearing the hat of partner and father/mother. Now it's time to find you. Maybe search the internet for some hobbies and then try some out. You don't have to like a hobby before you begin, usually the joy comes once you've started.
I recall from other posts that you are rather religious. Do you go to church often? Does your church run any social groups that you could attend? Have you spoken to your priest about recommendations for networking?
I don't think it's an embolism, I think you just let your heart feel again, and this was probably quite daunting, understandably so. Imagine you were still with your wife, would she want you to be cuddled up underneath a rock somewhere?
Don't give up just yet:)