Should I Still Marry This My Ex?

I had a friend who I loved so much. It was my sincere determination that I will marry her after graduation. Though I did not tell her openly that I wanted to marry her because I was afraid that should I tell her she might mismanage herself for the fact that she had been engaged. She knew quite well that I don't break/fail promises. She loved me so much then, but her change in character started when she got admission. I was in school then too about to graduate. One thing I know was that I tried my best showing her that I will marry her when things gets better through my body languages and indirect speech which I supposed she would have understood.

One faithful morning she called me telling me that somebody will be coming to her house and that she will be glad if I should come around to see the person. My spirits had never deceived me, I concluded that this girl was about getting married. Lo and behold that was it. Enveloped with guise pimple I didn't know how to tell her I will honour the invitation or object. But I concluded that I will not honour it though I didn't tell her. My absence pained her too because she called me weeks later, thanking me for not honouring her invitation. A sign that she was not happy.
To my greatest surprise I was planning on what next to do little did I know that she was pregnant already for the said guy. Few months later she called me telling me that her husband had an accident and died. I consoled her to the best of my ability. She delivered a baby boy two months after the husband's death.

Now, the boy is living with her parents grown and has started bursary schoool and she is not married again I guess. And she is ready to remarry in my own assessment because she has started showing me her brake light again knowing full well that I want to marry. I loved this girl but I don't know whether to propose to her as I now want to marry. My confusion is something like after math, whether this girl will still have feeling to her dead husband which may bring jeopardy to our family.