From the start I knew she didnt like the fact that I have 3 kids from a previous relationship and it was the only negative thing that she could find about us but I believed we could get trough that.

I can totally see why you were willing to look past it if you were really into this woman...like the instinct to do that is so strong, I'm sure, but this is just a decision that you can't make if you are looking for a life partner. Making tough decisions early on in unsatisfactory relationships can save you a lot of time and heartache.

Try to find somebody who is not just putting up with the fact that you have kids, or willing to overlook it. Look for somebody who is open and maybe even excited about the idea of forming a family. If you make it clear that you have kids in the early stages of dating, that is a natural conversation that should come up. If you get the sense that they are not open to the idea of kids (as you did with your ex), then you really do just need to make a decision to move on, unless you are 100% (fully) okay with having a more casual relationship.