One thing I can say that hasn't been an issue for me, is giving every man a fair chance to build or break my trust. While not always ideal for me, I refuse to sabotage a current relationship because of the lingering actions of someone who is and should stay in my past. This isn't necessarily easy for everyone and it's totally understandable. We've all had that one person to betray our trust so badly that we've memorized all their moves (and the red flags we should have caught during the relationship). The problem is, as soon as we see any similarities in someone else, the red flags and emotions overshadow our ability to be/think objective. Don't be that girl! It will jeopardize your future happiness with ANYONE else.
As soon as something is similar to an ex, your eyebrow raises and your body starts to produce the negative emotion associated with that ex. Now, the new guy is at risk of catching unwarranted heat because you've found an uncomfortable similarity. Each time this happens, the reaction is bound to get more dramatic and less rational until you eventually become unbearable to the new guy. Here's where the baggage label comes in. Once the new guy notices the pattern, he may label you as a woman with baggage or simply damaged goods. There will be some guys that will be forgiving and understanding of the situation, but if you can help it... DON'T BE THIS GIRL. It will get exhausting to the most patient of guys. This is probably the most common deal breaker with men (even when your actions are warranted). Nobody wants to be under constant scrutiny and/or accused of something that isn't true.
Additionally, do not train your friends to adapt your way of thinking when you see "red flags" in their significant other. Your red flags won't always be the next person's red flags because you have different experiences. More importantly, one should never have someone else's significant other under scrutiny based on their personal experiences. Don't be that friend and don't project! Do not police your partner (or anyone else's) based on your ex's crimes! You will end up lonely and bitter (and possibly friendless because, girl...).
How can you stop? Acknowledge that every person is unique and you are dealing with someone totally different from your ex. Even identical twins have different personalities. Know that things aren't always what they seem to be (especially when you're apt to be paranoid about certain things). When particularly suspicious, it's okay to do a reference point check, but don't check with someone that you KNOW thinks exactly like you. (I like to task my guy friends with this if I'm ever questioning my rationale). They're typically a good calibration point. Explain your thought process and it's origin to your partner to make them aware of your struggle (not to make being irrational okay). Communication is key. In this case you want to make sure they know your vulnerability so that they may be able to help you work through the issue.
It's fine to have hang-ups and weaknesses. This is just one you HAVE to learn to navigate or it will leave you lonely and incompatible with most.