When do you know he's serious?
Read what are the signs that he is serious about you and yes "I want to spend the rest of my life with you" it's not just a phrase!
He actively works on problems and does not sweep them under the carpet
He doesn't want her to end up hating him. He doesn't want her to be unhappy in the relationship. That's why he talks to you when problems arise. In the end, they come to a compromise and work to make things better. Do what needs to be done and don't pretend everything is okay. He doesn't ignore your opinion or act like you're dramatizing. Whenever something goes wrong, he takes it seriously because he is serious about your relationship.
He regularly checks to see if you're still happy in the relationship
It is not in his habit to assume that everything is okay. He doesn't assume he's the perfect partner. He actually asks you. He wants to hear how you feel. He wants to know what you think. He wants to make sure you're still excited about your life together. He creates open communication because he wants you to know that you can tell him anything.
He has made a plan for your future, or at least he is talking about your future
He knows if he wants to get married and, for example, move out of town, he knows if he wants children. He doesn't hide anything from you, and you don't hide anything from him. They are not waiting for tomorrow to think about their future together. They make plans for the future (or at least discuss the idea) because they can't imagine spending the rest of their lives without each other. They are a team and intend to stay that way.
He is constantly striving to improve himself
When he does something wrong, he doesn't make excuses for why he hurt you. He's not trying to change the narrative of the situation to make you the guilty party. He takes responsibility for what he did, apologizes, and actively works to improve in order to strengthen your relationship. He believes you deserve the best he has to offer.
He is truly devoted to you
He is faithful. He respects you. And he puts as much effort into the relationship as you do. He has left the days of being a "player" behind him, as he is ready to commit himself only to you. He is not interested in other girls. He only wants you. Forever.
It supports your greatest hopes and dreams
He believes that you have what it takes to succeed and encourages you to find it. He wants you to be happy in and outside of your relationship. He wants you to feel accomplished. He wants to make sure you reach your potential.
He treats you like his "teammate"
You are his equal. You are a friend to him. He always includes you in his decisions because he believes that we should create the future together. He believes they are in this TOGETHER!
