Can co parenting be peaceful

My first time postintg. Long story but my ex is obsessed with me and our shared son (4). We met during a breakup with my ex. My ex and I got together after I found out I was pregnant. He's been there from day one and was originally on the birth certificate. My son's father who started not interested took me to court when my son was around a year old got visitation and put on the birth certificate. Since then he's constantly driving by our house. During pick up and drop off telling me how pretty I am and asking me to contact him about us. When I try to be stern about us he threatens to take me to court for 50/50. He's self employed and lies about his income. He spoils our son and tells him it'll get better if he lived there. He tells my son to tell Mommy to come over and hangout with them or tell Mommy to come over and we can help combine or tells my son that if Mommy wants he will bring me lunch to work. My son's last name is still my boyfriend/ husband we got married a month ago and he's just now taking me to court to change my son's last name. It's so frustrating. Cause I feel in constant fear about going to court or he's driving by the house or what he's telling my son. My husband wants me to fight him changing his last name I don't think it'll work but am still going to try. But I feel like he's going to win and he's going to keep winning til he takes everything from me. He has told me on several occasions if we were together we wouldn't have to go through all this or threatens me about his lawyer doing whatever he wants cause he's known him forever. He knows the mayor and all the cops in his town. Luckily we live in separate towns but I feel like every time I turn around it's another threat or reminding me who he knows like it's a power trip. How do people deal with this? Any tips. Most of our conversations are during pick up and drop offs. Any way to not obviously record this? Would it hold up in court?