No, I think our body is going to handle it just fine. But of course do be careful of putting fear out to the Universe surrounding this pregnancy. If you are constantly thinking fear thoughts and miscarraige and such, then that is likely what you are to get back. Your body has nutured several babies very successfully. Focus on that. Let go of any fear before you get pregnant.
(okay so I guess that is something you can do )
Your son will not grow up without a father. It will only be a short time. There is someone else for you and him waiting in the wings. He won't come forward for a couple of years, b/c he doesn't want to pick up the pieces. That is not what this relationship will be based on.