You need to find a backbone then. Your parents, friends or whoever else, do not have to live with the person you choose to be your partner. Quite frankly, who you choose to have a relationship with, has nothing to do with anyone else.
As adults, we have to make our own choices in life and make and learn from our own mistakes. You need to be firm with your parents in future and tell them in polite terms, that your relationships are nothing to do with them.
Few parents actually believe anyone will be good enough for their child and probably will always have something negative to say. If you make it clear to them early on, that you will not tolerate nor listen to any negative comments, they are less likely to keep on at it.
I'm sorry to be so harsh, but this ex girlfriend of yours probably had a lucky escape. The relationship could never have been happy, when you allow people to influence your choices. It's unlikely you would have defended her against the criticism of others. Work on your own confidence and self esteem.
Also, there's no point living in the past and fantasising about what could have been. It didn't happen, so now you should look to the future, take control of your own life and make the things you want happen. People who sit back and wait for things to fall into their laps, rarely get anywhere in life.