The time for dating can count on how you build each other though at times it never counts. You can date for months and maybe for years but still end up separating. Most will not count the number of times they have been with you anymore. But instead, they will focus on who you have been all that time that you knew each other.
A number of reasons may contribute to your lover leaving you, yet you struggled to make it work. It is not only that she was the problem but also YOU. Always make a judgment basing on your downfalls if your lover decides to move on with another person.