Your boyfriend needs to get his situation straightened out first, and so do you. I know it will not be easy, but I advise you to tell your boyfriend that you have to step aside and allow him to focus on resolving his own situation without the distraction of the two of you as a couple.Encourage him to approach the Tribunal of the Diocese he belongs to and begin the annulment process.As I’m sure you know, a civil divorce does not dissolve a sacramental marriage.All it does is help settle the legal obligations to each other at the civil level.It most certainly does not do anything to their moral obligations at the spiritual level.Their vows before God cannot be dissolved by a civil court.That is my general overview of handling situations like you are in.Now you need to confront the specific factors before you can make an informed and wise decision.
God cannot call a person to a vocation when they are already in a vocation.
I also do not know if their marriage took place in the Catholic Church.
I am just going to assume it did and the marriage was not annulled.
Maybe He does ultimately have it in mind that you will be married to this man in the future, but that is not for you to assume, nor to plan, nor try to manipulate.
You need to step back and let God make this happen the right way, if at all.