In life, it doesn't mean that you will be rewarded if you give your feelings. Didn't you say that love is selfless? How can selflessness ask for something in return?
You love someone is an expression of your feelings. No matter how deep you love, it doesn't mean that the other person must love you. Even if the other person loves you very much, it doesn't mean that you can be together in the end. In real life, there is not only love, but also love without material foundation is very unstable and has no foundation. Talking about feelings without talking about material things is simply illusory in romantic months. It looks romantic but can't stand a little wind and rain.
Besides material life, there are other factors that affect feelings. Can your families recognize and accept each other? Whether there is a matching education and social relations. These will affect your further emotional development and whether you can finally be together.
Maybe two people are happy, happy and comfortable when they are alone. But when you come into contact with each other's family, you may have contradictions, and maybe when you come into contact with each other's social relations, you will have contradictions again. When it comes to interpersonal communication at work, maybe your different life backgrounds will give you different cognition and understanding. The root of these contradictions cannot be made up by love alone.
Therefore, it is normal for a person to fall in love and finally not be together. This kind of thing is in this material society.