seninle tanıştıgım zaman ben çok üzgün biriydim ve çok mutsuzdum şimdi ise sen varsın ve mutluyum seni çok seviyorum senin üzülmeni asla istemem.

here´s my attempt at the first sentence

The time when I met you, I was someone who was very sad and I was very unhappy.

şimdi ise sen varsın ve mutluyum. seni çok seviyorum, senin üzülmeni asla istemem.

now you are in my life and i am happy. i love you so much, i will never want you to be sad.

Ignore my attempt and look at the previous post

as for now, I have you and I am happy.

I love you very much.

I never want you to feel sad / to be upset.

(I wasn´t certain about the translation of the brown and green part.

but thankfully ikicihan & gokuyum have helped me understand)

ise can mean if or as for, but the sentence lacks punctuation.

varsın also has a few possible meanings

iyi ki varsın = it´s good that ... I have you / that you were born / that you exist

varsın olsun = let it be

Wait for a Turk to translate that part correctly. 

Ahhh, I see it has already been done, I´m too slow

we can ignore the "ise" word here. we can translate it as "but" (fakat/ama) if we have to.

the meaning of "ise" here, something changes, transforms to totally an opposite side.

here in first part, he or she is not exist, and in the second part he or she is exist. there is a total radical transformation and "ise" word tells us this change.

more example:

dün hastaydım, şimdi ise iyiyim.
i was sick yesterday but now i am good/healty/well.

eskiden fakirdim, şimdi ise çok zenginim.

i used to be poor but now i am very rich.

Açıklaman için çok teşekkür ederim ikicihan  çok faydalı

Şimdi ise sen varsın

Henry "ise" belongs to "şimdi" not to "sen" If you want to use "as for", you should say "as for now"