I'm up for a custody trail, and looking for advise

I just got married may 2nd, and my 5 yr old loves my husband, and has decided to call him dad. My ex hates that, and has been trying to teach him what a step-dad is. All my son see is that my husband is there for him when he needs him, and he thinks thats what dads do...therefor my husband is the dad. last week my husband moved his parents from florida back to our state (MA), and we had the U-Haul truck im my driveway for 3 days. When my ex saw the truck he called his mother and told her i was leaving out of state with our son. So she emediately called me to see if that was true... i told her NO, and proceeded to tell her, if I were going to leave the state all I would have to do is go to court and tell the judge what was happening and he would most-likely rule in my favor anyway. After I hung up the phone abruptly, I made it so she couldnt call my house with out letting my caller ID pick up her phone number. I didn't hear anything back from my ex's mother, and still have heard nothing from my ex. Two days later I took my son to gymnastics, during the class i was paged from an odd number when i called it back it was a county sherrif, and a state trooper, telling me I needed to go talk with a judge. When i figured out what this was about I assured them that I was not taking my son out of state. They belived me, and just told me they would meet me at home. When i pulled up they were waiting for me, and brought my to the court my judge was at (we get the same judge for all of our hearings). When i got there they inturupted a 2 day custody trial to hear our emergency case (i am 5 months pregnant, and on bedrests due to complications), when my ex started to speak it mainly regaurded his fear that i was going to change my sons last name, me wishing to move (wich I have been contemplating since before I split up with my ex), and my son calling my husband dad. The judge quickly told my ex, "she can't change the childs name without petitioning the court, and you will get notice of that." the judge had heard my ex say that I was going to kidnap my son before, and he had never been kidnapped, so the judge didnt quite belive that i was taking my son. And I have my son enrolled in kindergarden, so I have proof that i have no intention of moving anytime soon. After the judge heard everything we had to say he went into a 2 min. tirate on my ex about waisting everyones time, and then asked us both what we wanted. My ex said, I don't want her threatining to take my son away from me, and im sick of her being able to do anything she wants. Then the judge looked at me and I said, "I dont want him to beable to do this again, I want sole custody" the judge told us we would be getting a trail date very shortly and I'm hoping for any helpfull insights anyone has. I'm not looking to take away his visitation, I just dont want him to beable to get me arrested infront of my son for no reason whatsoever.