Co parenting

So my ex dumped me 3 months ago and I just had our son October 28th and I wanted to know how to co parent with someone you still love? He's made it perfectly clear he doesn't want to get back together and so I've decided to just co parent the best I can. Ever since having my son having to have contact with my ex has really set me back on my healing journey because when I was still pregnant I didn't have any contact with him in person and we rarely texted but now I have to see him and it's taking a real toll on me mentally. I have been pretty much crying the last 4 days because it's like torture having to be around him. How do I do this? I already told him we need to figure something else out because this isn't working for me but I'm not sure how to go about it as I've never had to co parent with someone i still loved (I do co parent with my other 2 kids father but that was a mutual breakup).. Any advice welcome.

Also I'm already on antidepressants because I was blindsided by the breakup and i got bad depression afterwards. Now I'm worried I'm getting PPD. Plan on talking to my doctor about it.