I think all of us like to think about the one who got away and we all have a fantasy of this one special person who rides up on his white horse and takes us away to live happily ever after.
But, the reality is that in the real world, we have people who depend on us. His one child is 13, which is a very impressionable age. Your three children, two are almost grown, but you have a 10 year old that still needs a lot of guidance. Now, I'm not saying that you could leave your husband and go back to Africa and be with your man and not be happy because you might be the happiest person in the world. I don't know. All I do know is that both of you will leave behind a LOT of people who will be hurt and that hurt will last a lifetime for them.
There would be so much to consider.....your children's reaction to divorce......your husband's reaction......family's reaction. The same thing would be happening to him as well. Then there's the financial aspect of everything. Should your husband remain in Canada, there would be airfare to transport the children back and forth and that would be expensive. They may all want to remain in Canada and you have to prepare for that, too.
I don't mean to put a damper on your plans because I truly want your happiness.