Marriages for gay men and lesbians could be conducted in Brighton and Hove by the end of the year.
If city councillors agree at a meeting next week, a special company called Civil Ceremonies will also be in charge of non-religious marriages, the renewal of marriage vows and baby-naming ceremonies.
For the first time, gay men and lesbians will be able to join in a ceremony and be put on a register along with heterosexual couples who choose not to go through with a religious marriage.
The proposals will go before the council's policy committee at a meeting on Tuesday.
If approved, the council hopes they will be implemented by the end of the year.
Liberal Democrat leader Paul Elgood, who first put forward the idea of a partnerships register, said he was delighted.
He said: "This is a historic first for the city. At last, lesbian and gay couples will be able to register their relationships in the city in which they live.
"This is such good news and I am delighted a way forward has been found after considerable legal problems.
"This is a very important first step in the battle for full legal recognition for lesbian and gay relationships.
"This will show the demand from the community for such equality, which is terribly overdue.
"A report says Civil Ceremonies would deliver the sort of ceremonies people wanted and commemorative certificates would be issued after each one."
Civil Ceremonies was drafted in to run the service after the council found it would run up legal problems if it ran it itself.
The company has already run a similar scheme in Manchester, which has been very successful.
Couples would enter into a contract with the company and the council would not make money out of it.
It is likely the ceremonies would take place in places already approved for marriage ceremonies, such as the Royal Pavilion and the Palace Pier.
Older Gays and Lesbian Forum said the gay community would welcome the new initiative.
Secretary Peter Otto said: "Of course, we are pleased this is happening. We already have a member who is doing unofficial ceremonies but it would be much better with the council.
"We are making inroads into gaining equality for homosexuals.
"The only problem is that it will be a very long time before this proposal is made a reality.
"But we must not complain as it is one more step to success."
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