According to the (fantastic) TB article, Sagar goes to Beneras because he realises he cant live without Vidya and not because he finds out the truth. Im so glad that will be the case and I think most of us wanted Sagar to realise that he is incomplete without Vidya.
BTW I found a translation for Tum Se Hi, for anyone who doesn't understand the words
CREDIT to translator.
TUM SE HI
naa hai yah paanaa naa khonaa hii hai
(It isn't a gain, but it isn't a loss, either.)
teraa naa honaa jaane kyun honaa hii hai
(If I don't belong to you, why should I exist at all?)
tum se hii din hotaa hai
(The day breaks only with you.)
surmaii shaam aatii hai tum se hii tum se hii
(The dark night comes with you, only with you...)
har ghaRii saa.ns aatii hai
(The breath never ceases.)
zindagii kah laatii hai tum se hii tum se hii
(Only you are part of every conversation, only you...)
naa hai yah paanaa naa khonaa hii hai
(It isn't a gain, but it isn't a loss, either.)
teraa naa honaa jaane kyun honaa hii hai
(If I don't belong to you, why should I exist at all?)
aa.nkho.n me.n aa.nkhe.n terii
(I am looking with your eyes.)
baaho.n me.n baahe.n terii
(I am touching with your hands.)
meraa naa mujh me.n kuchh rahaa huaa kyaa
(There is nothing mine left within me, what happened?)
baato.n me.n baate.n terii
(I am speaking with your words.)
raate.n saugaate.n terii
(My nights are your greeting gifts.)
kyun teraa sab yah ho gayaa huaa kyaa
(Why did everything become yours, what happened?)
mai.n kahii.n bhii jaataa huu.n
(Wherever I go,)
tum se hii mil jaataa huu.n tum se hii tum se hii
(it is only you that I meet, only you...)
shor me.n khaamoshii hai
(There is silence in the noise.)
thoRii sii behoshii hai tum se hii tum se hii
(There is slight unconsciousness that you cause, only you...)
aadhaa saa waadaa kabhii
(Sometimes half a promise)
aadhe se zayadaa kabhii
(is more than just a half.)
jii chaahe kar luu.n is tarah wafaa kaa
(This is how I shall be faithful to you.)
choRe naa chhuuTe kabhii
(May it never be lost or discharged,)
toRe naa TuuTe kabhii
(may it never break or rupture-)
jo dhaagaa tum se juR gayaa wafaa kaa
(that thread of loyalty that joined me with you.)
mai.n teraa sharmayaa huu.n
(I am your shy one,)
jo mai.n ban payaa huu.n tum se hii tum se hii
(I became like that because of you, just because of you...)
raaste mil jaate hai.n
(The roads are found,)
ma.nzile.n mil jaatii hai.n tum se hii tum se hii
(the destinations are reached only with you, only with you...)
naa hai yah paanaa naa khonaa hii hai
(It isn't a gain, but it isn't a loss, either.)
teraa naa honaa jaane kyun honaa hii hai
(If I don't belong to you, why should I exist at all?)