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.
Therefore, you are dating a married man, which you are not permitted to do.
The reality is you are in a drama that probably will never end.So if you want to do the right thing for your boyfriend, and for yourself (and for the children and all others involved), you will end the dating relationship.This is the right thing to do, and it will make God happy and He will bless you accordingly.That is a wonderful thing, and should be your primary focus above all things in your situation.I pray that you will not let anything or anyone disrupt your steps toward being received into the Catholic Church. Your entering the Catholic Church is the worst thing that can happen to the devil, so what you are going through is likely going to be used to shake your faith and perhaps attempt to get you to not become Catholic.
I am dating a good Catholic man who is divorced and has a son.