This is something I've never been too sure on.
While the experience of having a serious loving relationship was very nice and something I hope to have again one day, when it ended it left me pretty negative and hateful to this day. I have my ex entirely to blame for that, which in my book nullifies any positive times I had with her, since it was obviously all for nought.
I'm sort of in two minds, I mean, on one hand, for me, having loved and lost has meant real betrayal, which we all know really effects us long term (I don't know if I'm going to be this negative husk forever right now), but having never loved at all would mean I would be a little less wiser for not having been through the experiences I have, but I would also near undoubtedly be a happier person, because, not to sound emo or bitter or anything, but when me and my ex broke up, it took a lot of happy traits away from me.
Don't get me wrong, I don't want them back from her, I'd like nothing more than for her to become a 'missing person', but I'm sure there's been a noticeable change for those close to me.
This is probably the most thought out post I've ever done here. Good job OP.