Given its patriarchal, heterosexist history, I’m no fan of wedlock. I won’t be celebrating Marriage Week, coordinated by marriage lobbyists the Marriage Foundation, which starts today. But I like the idea of commitment and of couples having reciprocal legal rights, obligations and protections. It’s just that the marriage legal framework seems so antiquated and out-of-touch with the diversity of modern relationships. People can have marriage if they want it. I’ll always defend their right to make that choice – but many of us aspire to something better.

For starters, marriage law privileges romantic sexual love over often equally enduring, loyal friendships. Some lifelong friends share levels of devotion and commitment similar to those of many spouses. That’s why I favour a broader system of partnership recognition. Any two people who share a close, deep bond ought to be eligible for reciprocal legal rights towards each other. Instead of restricting these rights to people in a sexual relationship, they should be extended to cover all relations based on mutual care and commitment.

Strong, supportive relationships – whether between lovers or friends – are good for the people involved and have a wider social benefit. As well as enhancing an individual’s happiness and wellbeing, they strengthen a person’s ability to cope with adversity and diminish their dependence on the state. It is therefore in society’s interest to encourage and reward such relationships with legal validation and protection.

My proposed civil commitment pact would allow people to nominate any “significant other” in their life as their next of kin, inheritance beneficiary and their nominee for host of other mutual rights. This could be a partner or lover, but it could also be a sister, carer or best friend.

Many non-sexual friendships are just as loyal and enriching as relations between people in love. They too should have legal recognition. There is no sound reason to restrict partnership rights to people in sexual relationships.

With many marriages ending in divorce, and over a quarter of households comprised of single people, friends now play an important role in many people’s lives and support networks. Surely it is wrong to discriminate against two friends who have a strong commitment to care for each other, just because they are not married and do not have sex? As well as permitting people to nominate any significant person in their life, a new partnership framework could also offer flexibility and choice with regard to rights and responsibilities.

Within our society we see a huge variety of relationships. There are people who live together, and those who live apart. Some share their finances; others maintain financial independence. There are couples with children and those without. The law should reflect and support these diverse relationship realities. The one-size-fits-all model of relationship recognition – exemplified by marriage – is no longer appropriate.

My civil commitment pact would let people select from a menu of rights and responsibilities

My civil commitment pact would let people select from a menu of rights and responsibilities. This adaptability would enable them to devise a tailor-made partnership agreement suited to their own particular needs. Some people may, for example, want to designate another person as their next of kin, but not wish to confer on that person other rights or responsibilities. The law should let them make that choice. Marriage, and “marriage lite” civil partnerships, don’t give people these options. It is all or nothing.

In the case of couples in a love relationship, permitting them to choose from a menu of rights and responsibilities has an additional virtue. It would require them to sit down together, negotiate and sign off their obligations towards each other on each specific issue, such as property inheritance and, if they have children, joint guardianship.

This point-by-point negotiation would compel partners to examine their relationship more closely and think through in greater detail the implications of entering a partnership agreement. It might lead to wiser decisions and more enduring commitment. With marriage, by contrast, there is no obligation on the couple to discuss the detail of their mutual rights and responsibilities. They simply sign a certificate, without any need to negotiate the particulars.

My “pick and mix” system gives recognition and rights to both love partners and non-sexual close friends. Offering a modern, flexible alternative to marriage and civil partnerships, it would benefit all those who are in relationships of reciprocal devotion and care.

• Peter Tatchell is a human rights campaigner and director of the Peter Tatchell Foundation