Hi, I googled to get some answers or advise.
Background, grew up in Christian churches, Have been looking into Catholic Church for many years. a year and a half ago I decided to go even deeper into my need to  become Catholic. I am attending RCIA.
About a year ago I met a guy. He was going thru a divorce. He is Catholic. Born and raised. Kids go to Catholic schools etc. I felt drawn to him because of his faith and what I was going thru at the time, I felt GOD had introduced us. We stayed friends thru the finalization of his divorce. We are dating now. I truly care deeply for him.
Now heres where the advise comes in. His ex left him,, she filed for divorce.. He didnt want it. He tried to change her mind. Then he accepted it after she filed and he moved on.
When he met me , he had already went out with a few other girls. In January his ex found out there was a me. And she went crazy. She wasnt technically and ex yet. so she tried stopping the divorce and she called me and followed me and texted me. She said I was the reason THey were getting a divorce and she told thier children this too. I didnt even know him when she left and filed. She has done nothing but send him text everyday all day. sometimes up to50 a day. She has approached my 6yo at school to tell her to stay away from her kids, and made her cry. She text him that she wont stop texting him until he either gives her the kids and goes away or talks to her and goes to counseling. He rarely replies to any text from her except to tell her to leave him alone. She has went to the school to let them know about him and me and tells teachers , principles, priest, other parents, that I am the cause of their marriage breaking up. My daughter goes to school there, I guess I just dont understand her claiming to be catholic and constantly screaming at my boyfriend about thier vows and how he lied to her. She is the one that left and she had an affair and still to this day lives with the guy she had the affair with. I just dont know what to do, SHe wants him back and has said so. even yesterday she texted to him that "even my boyfriend knows I would come back to you in a heartbeat".
Should I step aside even though he is divorced and he says he wouldnt ever take her back and he has told me he loves me.?
I wonder if thats what God wants me to do?   I am so confused.
I really love spending time and hanging out with him. We can talk about anything. We have fun together. But her constant harrassment is too much. I dont know if it is God directing her, or Satan....

A legal divorce is not an end to a Catholic marriage. You're socializing with a married man and giving him motivation to not mend his relationship with his lawful wife.

Move on and find a single Catholic man to court.

so according to the Church he either needs to reconcile or seek an annulment?
and unless/until then, friends only?

From the sounds of it, not even friends. Cut it off entirely.

Just me,
After reading through you post, I can honestly see that you are very confused.  This is a traditional Catholic forum, not a NO forum and you will get very different answers I am afraid.  

Hopefully this will help you understand things more clearly.

Once two people are validly married, they are always married.  When these two people divorce, neither of them can ever get married again, unless one of them dies.  Marriage is until death.  Dating a divorced person is adultery.  

In certain cases, however, the Church can be asked to determine if there actually was a marriage to begin with.  This is what happens in the process of annulment.  Presently, the NO Catholic church in America grants a lot of annulments.  It is quite arguable if these annulments are actually deserving or not.

Criteria for annulment is quite serious--mental illness, drug/alcohol abuse at time of marriage--etc.  Just because two married people have problems after their marriage does not invalidate a marriage.  

I understand that you friend did not ask for a divorce.  He was basically abandoned by his wife.  This is a sad situation, however this does not give him license to enter into an adulterous relationship with another woman.

You, personally, have only one option.  That is to abandon all ideas that you can have a sincere relationship with this man. He is married.  Even engaging in a friendship with him might lead to something sinful.  IMO, it's best to leave it alone.

Your friend has other options.  He can attempt to reconcile with his wife (which is the best option, especially if children are involved), he can seek and annulment (which he'll probably get in the NO), or he can remain single and celibate.  

Hope that helps.

Yes thank you,
THat helps tremendously

Sorry, you did say she was Catholic.  In that case, their marriage is valid.