The definition of adultery is to have “sexual intercourse”, or to be completely clear on this, “penetrative sex” with another person (not your spouse) of the opposite sex whilst you are married to your spouse.

It’s surprising how many people believe that because they are separated (not divorced) from their spouse and having an affair with someone else, that they are not committing adultery. They are. If you are divorced from your spouse (i.e. your ex-spouse) and having an affair, then this is no longer adultery for you – although the person with whom you’re having an affair might be committing adultery, if they are still married.

If you are not married but are co-habiting with someone else and have penetrative sex with someone else, then this is not adultery. You may be cheating. You may be unfaithful. You may find yourself thrown out on your ear… You are not adulterous.

Can you commit adultery if you are gay? This is an interesting point. Curiously, if you are in a Civil Partnership and have penetrative sex with someone else, this is not adultery because you are not married. However, if you are in a same-sex marriage, then you could be committing adultery if you are having penetrative sex with someone other than your spouse but significantly and rather bizarrely, it is not adultery unless that other person is of the opposite sex.

Read what you like into the legislation as regards this last paragraph but if you are in a same-sex marriage and have an affair with someone other than your spouse but that other person is the same sex as you, this is not adultery. Again, it may be cheating. It may be being unfaithful but it’s not adultery.

So, Are you Committing Adultery?

So, in a Civil Partnership, where there cannot be adultery and in a same-sex marriage, where it is not adultery if the other person with whom you are having an affair is of the same sex as you, then the ground for bringing both the Civil Partnership and the same-sex marriage would have to be unreasonable behaviour (unless one of the other grounds was chosen e.g. separated for two years but with the other party’s consent, separated for five years or lastly desertion). One of these factors must be used to show that the Civil Partnership or Same-Sex Marriage had irretrievably broken down.

Whilst on the topic of differences between heterosexual marriages and same-sex Civil Partnerships and same-sex marriages, it would not be possible to bring a petition to annul a Civil Partnership or same-sex marriage on the grounds of non-consummation. Some of the present legislation can seem a little odd in the way it distinguishes between heterosexual and gay relationships. The reasons behind that are known only to the parties who originally drew up the legislation. What is clear is that the question about whether you are committing adultery or not is not always as clear as one might think!

You may have questions about the matters discussed in this article, or on another area of Family Law? Need a divorce

Please call the author, Elizabeth Leah, or another member of the rhw Family Team on 01483 302000 or email: