Different perspectives can be helpful, absolutely. But your current partner probably isn't the best person to be looking to for a different perspective when it comes to other people you might have dated. Aside from the fact that they don't even know those other people, there's the simple fact that they're not likely to tell you that you should have chosen the other person. You put them in an awkward position by bringing up these other people from your past.

If someone is questioning whether they made the right choice, a therapist, relationship coach, or even just a good friend are all better choices. They can be more objective because they're not in a romantic relationship with you. And you avoid the awkwardness of making your partner question the relationship and feel insecure.