The honest answer is no, you do not have to invite anyone. The useful answer is that you need a rule you can state out loud without it sounding like it was invented to exclude one specific person, because at some point you will be asked to explain it.
Pick a rule, then apply it to everyone
The common convention is that established partners are invited and casual ones are not, with the line drawn at married, engaged, or living together. Some couples use a time threshold instead, along the lines of together more than a year.
Any of these work. What does not work is deciding case by case, because the moment you make an exception you have converted a policy into a series of judgements about individual relationships, and every one of those judgements is now something you can be challenged on.
Write your rule down before you start listing names. Then apply it to your own side first. If it produces an answer on your side you are not willing to live with, the rule is wrong and you need a different one, not an exception.
The reciprocity trap
A recurring version of this question is about someone whose wedding you were not invited to, or were invited to without your partner. The instinct to match their decision is strong and it is worth resisting.
Their guest list was shaped by their budget, their venue capacity and their family, none of which you can see from outside. A cousin with a large family and a 60-seat barn had fewer choices than you might assume.
More practically, a decision made to settle a score reads as one. Guests notice patterns, and a single conspicuous omission invites questions you then have to answer at the reception.
What the numbers actually cost you
It helps to know what a decision is worth before agonising over it. The average spend per guest at a UK wedding in 2026 sits at around £272 to £278 depending on which industry report you use.
So six additional partners is somewhere near £1,650. That is a real number and a legitimate reason to hold a line. It is also, for some couples, less than they assumed and cheaper than the family friction.
Work out your own figure rather than using the average. Divide your catering and drinks quote by your guest count and you have the marginal cost of one more person. Whether that changes your answer is up to you, but it is better to decide with the number in front of you.
Worked example: what the rule produces
Say you go with married, engaged or living together. Now run it across a real set of people rather than in the abstract.
Your cousin and her husband of six years. Both invited, obviously. Your cousin's brother, who moved in with his girlfriend last spring. Both invited, and you may not have met her. Your closest friend from university, who has been seeing someone for eight months and they do not live together. She comes alone. Your partner's colleague, who is engaged. Both invited, even though you have met the fiancé once.
Look at what that produces. Your oldest friend attends alone while a colleague's fiancé you barely know gets a seat. That feels wrong, and it is the exact point at which most couples abandon the rule and start making exceptions.
The rule is still working. It is doing what a rule does, which is producing an answer you can defend rather than an answer you like. If you cannot live with that specific outcome, change the rule for everyone. Together more than a year would invite your university friend's partner and still exclude a three-month relationship. What you should not do is keep the rule and quietly make one exception, because the person you excluded on the same grounds will find out.
Where cost genuinely bites is the threshold effects. Six extra guests can mean one more table, which can mean one more centrepiece, more linens, and in some venues tipping over a capacity band into a different room hire rate. Ask your venue where their next threshold sits before assuming the cost is simply per head.
Word the invitation so there is nothing to interpret
Most plus-one disputes start with an ambiguous invitation. If the envelope says only the guest's name but the invitation inside says nothing either way, some people will assume a partner is included and some will not.
Name every invited person explicitly on the invitation itself. If a partner is invited, use their name rather than writing guest, which reads as an afterthought and tells someone their partner was not worth looking up.
If you are inviting someone without a partner, the invitation naming only them is usually enough. If you want to be unmistakable, a line on your wedding website explaining that you have had to limit numbers and are only able to invite named guests does the job without singling anyone out.
Say it once, in writing, in a place everyone can see. Repeating it individually to people you expect to object turns a policy into a confrontation.
When someone pushes back
Someone will. Usually a parent, occasionally the guest themselves, sometimes several weeks after the invitations went out.
The answer is the rule, stated plainly, with the reason attached. We have a capacity of eighty and we have invited partners where people are married or living together. Nothing about that sentence is negotiable and nothing in it is personal, which makes it hard to argue with for long.
What weakens it is explaining more than once, or offering to think about it. Both suggest the decision is open. It is fine to say you understand it is disappointing and that the answer is still no.
If you do end up making an exception, apply it to everyone who meets the same description rather than to the one person who asked. Otherwise you have taught people that asking works, and there are usually a few weeks left for others to ask.
Sorting your guest list?
Kismet tracks households rather than individuals, so partners, plus-ones and children stay grouped, and your seating plan already knows who belongs together.
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