I was cheating on my girlfriend of five years for a year, but I just ended it.
Why would you get into a second relationship while still in a first one?
The more women the better!
That's a terrible and disrespectful attitude.  You should only be dating one person at a time unless it has been made clear that multiple partners are fine with the both of you.  Your other girlfriend will probably leave you when she finds out.
I'm hoping that she will forgive me and want to stay with me anyway. That's why I'm doing it this way.
I think that is a lot to hope for. Some people can't get over cheating and I would set your expectations accordingly.