How can you tell when LOVE is falling apart?

I am having hard time to know if my bf is still the same person I met the first time. He keeps on making promises but always fail to do it because he is too busy with his work. Sometimes I feel neglected but I don't want to show him that I am not understanding when it comes to his work. I tried breaking away with him but I don't have enough reasons yet. Can someone share with me if there are other ways to know if a relationship is falling apart?

Even the busiest person like the president can find precious time with his family. When he gives you his time, I think the quality you spent together matters most. If you find him different, less interested with your life, forget your birthday or anniversary...maybe you should do the same to him. See if he misses you.