Feeling wanted, desired and cared about is a basic humanistic desire we all have. It is one thing to feel it from your family, but we all want that one person that will ride or die for us. As we get older, relationships must be built on this foundation of support, commitment and desire to live and grow together.
You need to position yourself in a place that allows your partner to not only feel special, but you need to say it. If you are someone that is good looking and pretty popular, expect a little insecurity of the other person when it comes to exes, or people who appear to have feelings for you although you may not feel any. Plan for that. In some relationships, public affirmations and annocuements of what this person means to you will send all the message you need. In some relationships, a simple and private conversation will do. But most times a mixture of the two is what works best.
You can not control the actions of other people, but you can be very clear in your message to them. Be clear!! Do you remember the first time your significant other said something cute to you, first time they said they love you, the first time they put in some effort to make you feel special? It is vital that you both work to recreate moments like that for each other. Being made to blush is a great thing. Stop running from it. Make that your goal. It's this effort that will create a bond that will easily survive the future dumb arguments, disagreements and potential mishaps. Take the time to grow that bond.
Someone who is unclear of your value will send you signals. Pay attention. Understand that not everything needs to be discussed but when you feel like you aren't a priority, say something. You need to give people a chance to correct behavior before you run. But don't settle. Set clear lines of what is acceptable and what is not.
The true test of any relationships comes in time of tragedy and in the era of dissonance. At the end of the day, the last thing that you both should have to count on is each other. If you don't have that now, that needs to be the goal or get to steppin'. If you do have that in your relationship, cherish it and protect it at all costs. Let no one take that feeling from you.