Broken up but still friends but Idk what’s to do

My ex and I were dating since November. A little bit of background they are older then me by a decade I’m 21 and they are 32. Despite the relationship wasn’t perfect on their part we greatly enjoyed each other’s time and they felt a connection they have never had with anyone before. It was my first serious relationship and their first serious relationship in a really long time.They said I did nothing wrong in the relationship and actually did everything perfect and gave more than they thought they deserved. They wanted to break up because They couldn’t take the constant mental battle of trying to be okay with dating someone so much younger than them despite they started the relationship. My parents and family were approving of them and even encouraged the relationship once it progressed to being serious. When I was in their presence the relationship felt right and good but when I wasn’t with them they second guess themselves and felt wrong and guilty. They didn’t want to end the relationship but they wouldn’t be able to handle the anxiety and stress that came with it. They wanted to stay friends and keep in touch/hangout as they saw me as valuable friend and one of only two female friends they have. The other being a married woman with kids they rarely talk to. I don’t know how to navigate being friends with my ex when I still want a relationship with them. As well I’ve never been friends with an ex in my previous relationships they ended toxically or I got ghosted. I don’t know what to do to stay in my lane and get over my feelings of wanting a relationship with them.