I think about you everyday and night.
Mein tumhare baare mein din raat sochta/sochti rahta/rahti hoon.
You are the best thing that has ever happened to me .
Tum Meri zindagi ki sabse behtareen cheez ho.
The love that I hold for you in my soul is greater than an ocean or the sky above.
Meri aatma mein tumhare liye jo pyaar hai wo samudra se gehara aur aasma se unchaa hai.
Please forgive me for all the hurt that I have caused you.
tumhare saath jitne bhi bure salook kiye hai uske liye mujhe maaf karna.
I love you, and I always will until the day that I die.
Main tumse pyaar karta/karti hoon aur marte dam tak karta/karti rahoonga/rahoongi.
You are the light in my eyes, the happiness in my heart, and just the thought of you leaving me breaks me into small and countless pieces.
tum meri aankhon ki roshni ho, mere dil ki khushi ho aur tumhare mujhe chodne ke vichaar se hi main kayi chote aur angeenat tukdo mein tut jaata/jaati hoon.
The day I met you was the day my life began.
Jis din main tumse mila/mili usi din meri zindagi ki shuruvaat huyi thi.
I will forever be grateful that you came into my life .
Mein tumhara hamesha ke liye abhaari rahunga/rahungi ki tum meri zindagi mein aayi/aaye.
Together we're perfect, and I will enjoy enjoying spending the rest of my life with you. I love you more than words can say.
Hum dono ek saath behtareen hain aur mein tumhare saath apni baaki ki zindagi bitana chahata/chahati hoon. Main tumse lafzon se jyaada pyaar karta/karti hoon.
Now when I look at your picture, I miss you lots - all day and all night.
Ab jab main tumhari tasveer ko dekhta/ dekhti hoon, main tumhe saara din aur saari raat yaad karta/karti hoon.
Note: when you see words like karta/karti, dekhta/dekhti, sochta/sochti, rahta/rahti etc. use 1st one if you're a male & 2nd if you're a female. In your case, you should omit 1st word & keep karti, dekhti, sochti, etc. as it is in the sentences.