There are a lot of things I don't understand

There are a lot of things I just do not understand in life. I do not understand why certain things happen or why things go the way they do. Like why did God have to take my 25 year old cousin so suddenly? Why when I finally get to a good spot in my life do things go awry so much? Why does this one person who seems to fit in so many ways and he has all the qualities I want in a husband, but things never seem to work out the way that they need to in order for him to be my husband. I don't understand it. And because I don't understand these things I feel the need to protect myself from them. So I say things and close myself off.
What I do know, is that right now, this is the position I'm supposed to be in. I'm supposed to be single and figuring myself out and I'm ok with that.I still hope that eventually we will be together again, but at the same time I know very well, that there are probably reasons we're not together now and maybe we're just not right each other. I feel in so many ways that we are right for each other, but listening to my heart has hurt me so often before that I don't want to continue to listen to it, because if it was right, wouldn't it have worked out before? Anyway, I don't really have words of wisdom right now because I don't understand a lot of these things.