Im not saying this is you, OP, at all. But its made me think...to be totally honest, as someone who had long (18+ months) relationships right from the beginning of dating at 15 and also had lots of people around me who did the same... my mum struck just the right balance I think, because if I was there, she gave me a cuddle and invented excuses to do stuff more and then probably booked us a little treat to cheer me up, if I was away she would ask if I wanted her to ring and then probably find an excuse to ring me on the pretence of something else then check in on me. She was sympathetic, and showed me love, but breakups were part of life and very much something that you dealt with as well as regular life. Its meant that I deal with breakups very well emotionally, because I know I'll be fine, life moves on, my mum is there if I need.
The people I know whose mum's would rush to their aid, use words like 'she's devastated', encourage them to put normal life on hold, spend time endlessly going over it etc, act like they've fallen ill... yeah, the world stops for them every time they have a breakups and they talk and act like they are DEVASTATED.... interestingly, I also find these people are the least realistic about relationships ending. As younger people, they seemed to come from the default assumption that every relationship is intended to last forever and that means you must do ANYTHING to save it and failing is a TRAGEDY. The same people who would never be able to understand that there is no ideal way to break up with someone, so all actions by the other party are villianised. The same people who then think the default is to hate your ex and everyone in your life think terribly of them, and anything outside of that is weird as they are obviously IN THE WRONG.
Basically, I think that the way people behave with their kids around breakups, the language they use etc, can often actually NOT be supportive and in fact is not thinking about the fact you need to be showing a child its okay to be sad, mum is here for you, but life moves on. People obviously work from their own experiences and non of us are perfect. A parent shouldn't be dismissive, and be conscious that all kids are different But I can see as an adult how many people have actually set their child up to feel more hurt, by talking and acting like its a MASSIVE deal. Breakups are part of life and we need to talk more about them when things are good.