@Gracy,
I'll be brief as I can be. Here's the crux of it, from my POV:
"... Leaving behind their 6 month old baby boy."
Whoa! All this that happened has to be so incredibly painful. Is he possibly looking for a partner to help him take care of his young child? There is so much tragedy there for any one human (even with the help of family/friends) to sort through. My imagination strains to think that someone would do this without some form of counseling.
However, some folks are capable, albeit a handful; however, are those that can do this without professional help capable of a loving intimate relationship within 3 yrs? I have no idea but you tell about his suffering over those 3 yrs. How is his 3-yr-old child doing and who is taking care of the child while he works?
A lot of lose ends there. I think after seeing you write that he 'flaked out' a few times that indicates he's either ambivalent or overwhelmed. Back off and let him come to you.
Let time sort this out without your forcing his hand without your being his safety net to open his eyes as to where he's straying off the path.
I wish you the best, but it's a tough road he has. He's not jsut a widower, he is the surviving partner of a suicide. Before the suicide , there could have been a depression that wasn't being dealt with. And why wasn't it deal with? Or was his wife's suicide related to wrong or badly prescribed meds and chemistry gone horribly wrong. Too many things to sort through to know where to start.