Is your boyfriend going abroad to study or work? My husband's company sent him to study abroad for a year, and I often flew to see him. If you have the conditions, you can also fly frequently.
If the financial conditions do not allow, you can send a few boxes of DIY chocolates, on which you can engrave different words and small patterns, and tell him that each chocolate in it represents your longing for him. Let him eat one when he misses you. This is irreplaceable by chocolates sold outside, and you can send more if it is not enough.
In addition, add a fresh rose and a gold-plated rose. The fresh one represents your flower-like age and that beautiful love, and the gold-plated one is like the eternity of love. These two flowers represent your lifelong friendship. I wish you happiness.
No one knows who will be the person who will accompany you throughout your life in the future. I just want to say that you should grasp the happiness of the present and cherish the present.