Marriage or civil partnership – what’s the difference?
A marriage ceremony is a verbal contract given in a ceremony. A civil partnership is a signed contract (a ceremony is optional).
A marriage consists of a husband and a wife and a civil partnership consists of civil partners.
A civil partnership is a legally recognised union that grants same sex and opposite sex couples similar rights and responsibilities as married couples. This legal recognition provides couples with rights and responsibilities, including those related to property, inheritance and pensions.
Like a marriage, a civil partnership can only be ended if one of you dies or by applying to court to bring the partnership legally to an end. This means if you want to marry or form a civil partnership with someone else in this, or any other country, you will have to have your existing civil partnership dissolved legally through the courts to obtain a dissolution, as you would do with a marriage to obtain a divorce. This is regardless of whether the country you are in recognises civil partnerships.
Marriage and civil partnership in England and Wales (GOV.UK)
Recognition overseas
Marriage – an opposite sex marriage formed in England and Wales will be recognised internationally. Same sex marriages formed in England and Wales are recognised in many countries but, if you're going abroad, you should seek advice about what rights you might have under the law of another country.
Civil partnership – same sex and opposite sex civil partnerships formed in England and Wales are recognised in many countries but again, if you're going abroad, seek advice about what rights you might have under the law of another country.
Conversion – you can't convert an opposite sex civil partnership to a marriage in England and Wales. You can convert your same sex civil partnership into a marriage. More about converting same sex civil partnership into a marriage (GOV.UK)