What can I say to people who say my poly relationship isn't a real relationship or say things like I need to choose one or ask who I love most?

You could point out that someone asking that is like asking a parent with multiple children "Which of your kids do you love the most? You have to choose one, otherwise it doesn't count." Love is love so long as the people involved all agree, no one has the right to belittle your relationships.

I would tell them they should be so lucky to love and be loved in such a way and nobody can dictate the way you choose to love, whether it be with one person or five. What works for you does not have to work for them.

You don't owe an explanation to anyone, if that is how you live, and what makes you happy, then what they think, or say, doesn't matter. If you feel that you do need to explain, or tell them something, tell them what you feel they need to know. That this is YOUR life, what you are happy with, etc...

Say that although they may not agree with your lifestyle, that you and only you and consenting partners can determine the type of relationship or type of love you wish to pursue. As long as your relationship is based on mutual respect and consent from all partners, your relationship is just as valid as any other. Gently remind them that even the most basic and socially-normative or common relationship can imperfect, and can be filled with dishonesty, anger, abuse or uncaring behavior. Your relationship, filled with happiness and love is as important as any other. All people are different, it is okay for others to not understand. Explain to them that you are happy, your partners are happy and that you wish to have the same respect as they would expect from you of their relationships.

You are not required to say anything. This is your relationship and nobody else's business. If you are comfortable with your sexuality and the relationship you are in, then don't even consider what other people are saying because ultimately, only you will truly understand your relationship. If they begin to become harmful or harass you, you can 1. tell them their opinion does not effect you, and 2. report them, or tell someone what they are doing and you can work out the problem.

What do you feel like you want to say to them.? What does the relationship feel like to you, do it feel real to you?

Being poly myself and have been told these things make this both easier and harder. I try to ignore the hate because it will always be there. But if you must say something, stand your ground. Maybe write something ahead of time and memorize it so you won't get off topic. Do what's right for you. Push yourself so you can be respected but still be seen as respectable. You are valid. Don't let people push you around, but you need to understand that not everyone gets this. Its sort of like how some lesbians are still transphobic ect.

You can tell them that all people involved are consensual, happy and in love, and that's all it takes for a relationship to be real. You can ask them how do they know they love their partner, and then say that it's exactly how you feel about all your partners. And if they keep judging you after that, just tell them that even if they don't understand they have to respect it. Apparently not all people are ready to understand how complex and diverse love can be.

Unless you have experienced a relationship like mine you shouldn't pass comment on it. I am happy and that's what matters to me