Giving wedding money without receiving an invitation

Two months ago, I saw that a young male employee I used to work with was getting married.
Even though I didn't receive an invitation, I thought it might just be awkward for him to send one, so I sent some wedding money.
But since the wedding, there has been no word from him at all.
Usually, people at least send a formal text message or something, but since he hasn't even done that, I'm starting to regret doing it.
I personally had a good impression of him, but now I'm seeing him in a different light.
I don't know if I'm just being old-fashioned, but anyway, from now on, if I don't get an invitation, I'm just going to mind my own business..