Walter Rinder is an American humanist writer who was born in the ‘30s but was most prolific in the ‘70s … one of his famous works was published in 1984 as an essay called “ The Spectrum of Love”. His writings are an exploration of the concept of love and of the commitment that underpins love of all kinds really. He is gay and that is neither here nor there, except for in our current historical context, which contests the notion of love in marriage exclusive to a man and woman.
Here is an excerpt which I’ve used in ceremonies :
“ For me to love is to commit myself, freely and without reservation.
I am sincerely interested in your happiness and well-being.
Whatever your needs are, I will try to fulfill them.
If you are lonely and need me, I will talk.
If you need the strength of human touch, I will be there.
If you need to be held, I will hold you.
I will try to be constant with you so that you will understand the core of my personality and from that understanding you can gain strength and security that I am acting as me.
I want to become a truly loving person.
Knowing you has opened me to a new and different understanding of what a loving attitude and way of life can mean.
It is my hope that our lives may be a continual renewal of our love for one another and other people.”
You could use this before the vows are exchanged.