I'll say its you.

You who fill colours in my life,

You who make it worth,

You who are my inspiration,

You whom I dearly love.

Yes, it's you throb of my life,

Yes, it's you breath of my life,

Yes, it's you my desire,

Yes, it's you my burning fire.

Let them doubt how can it be,

Let them cry out it cannot be,

Let them think I am mincing words,

Let them know I am in love.

Yet I continue to appreciate,

Yet I love her beyond compare,

Yet I have her by my side,

Yet I love her she is my pride.

Nalini my love for you I write,

Nalini my life for you I write,

Nalini my heart for you I write,

Nalini my throb for you I write,

Note the first four lines are written 

in bold as they are a part of a challenge

 rest is my answer.