The act does provide for a 'Cohabitation Agreement', which is intended to provide some financial protection in the event of a break-up. However, the courts can either vary or set aside such agreements, considerably weakening their effectiveness.
Irish cohabitation legislation is unique. Cohabitants in the UK have no similar rights and generally, in similar jurisdictions, such common law marriage is virtually unknown.
The reason for introducing civil partnership was clear - same-sex couples could not get legal status, and thus protection, for their relationships.
This was not the case, however, for cohabiting opposite sex couples - they only had to take part in a marriage ceremony to get this legal protection. Furthermore, with this act, same-sex couples then had a similar choice, i.e. to enter a civil partnership.
Thus the reasons for introducing these rights and obligations for all cohabiting couples is not at all clear and nor are the consequences, intended or otherwise.
There is also a crucial difference between being either a spouse or civil partner and a qualified cohabitant - the latter legal status is essentially 'foisted' upon an individual simply through the passage of time.
On the other hand, no one becomes a spouse or civil partner unless they choose to do so and also take an active part in the required official ceremony.
It is possible the intention was to financially protect opposite-sex couples in existing long-term unmarried relationships (even though they already had access to gold-plated protection simply by getting married).
On the other hand, an unintended consequence could be that individuals with sufficient assets and income to live with and support a less well-off partner are no longer willing to do so given that, after two or five years, they lose effective control over their income and wealth and are potentially at the mercy of the courts should the relationship break down.
The potential financial exposure for a better-off partner is also increased by the fact that the key objective of Irish family law is what is called making 'proper provision', i.e. ensuring, as much as possible, that both parties and any dependent children are financially provided for after a break-up.
Such provision is also typically ordered by the courts, irrespective of which party contributed what financially to the relationship or marriage.
It is highly likely that there is now a significant number of individuals who are qualified cohabitants but are unaware of their legal status, which could carry serious financial consequences - either positive or negative - should their relationships break down.
The introduction of this new legal status seems like an extraordinary intrusion by the State into the way individuals choose to organise their lives, particularly where there are no dependent children.
If two individuals choose to live together without getting married, then surely one has to accept that this is what they wish to do and are entirely comfortable not being married.
Traditionally marriage has been revered in Ireland, particularly in terms of societal cohesion and family values. However, we now have this new legislation which certainly waters down, if not eliminates, the need to ever get married, at least from a financial view.
This analysis is entirely financial in nature. However, this is also the focus that largely emerges from any review of Irish family law regarding relationship breakdown.
The textbook 'Divorce law and practise' by Geoffrey Shannon is a well-known reference source.
A quick review of its contents index shows that with the exception of one chapter on child guardianship, custody, access and welfare, the rest of this text is almost entirely concerned with financial provision.
We can expect to see increasing numbers of estranged 'qualified cohabitants' appearing in the family courts.
Irish family law gives judges considerable discretion. It will be interesting to see if there is a level playing field in the manner in which spouses, civil partners and qualified cohabitants are dealt with.
Oliver O'Shea is the founder and CEO of Lawonline.ie