"This might be because they fight a lot, even publicly; they never show affection; they show disrespect or rudeness to each other; they can't say a kind or supportive thing about each other," Shaw says.
"Sometimes we benchmark our own relationships accordingly: 'Thank goodness we're not like that!'"
But there are a lot of myths about how relationships should work that get tossed around, she says.
"For example, couples shouldn't fight; that opposites attract; that it is critical to have common interests; that distance makes the heart grow fonder, and so on. Some couples believe that getting help for your relationship must mean you are in deep trouble, as sex and love should 'happen naturally' and you shouldn't have to work at it."
Couples might manage their differences well when they're not under stress - for example, if one is quieter and the other more social. But during a time of stress like Covid, the differences can become a bone of contention. The quiet one might be handling it quite well, while the other is in need of social time.
"Before long the quiet one is seen as passive, inadequate and not offering the relationship much, and the extrovert is seen to be needy, demanding and critical."
Other couples have poor fighting behaviour, she says.
"The issues that they are battling over are perhaps quite small, and to another couple perhaps quite manageable. However, for some, it might get nasty and personal when they argue, or one runs away and refuses to engage, or the other cries and sulks, and the argument ends up lasting for days."
But research over the past few years shows that the amount you argue, what you have in common or the differences between you are irrelevant to whether you have a successful relationship.
The things that are most destructive to relationships are repetitive behaviours like criticism, defensiveness, contempt, and silent treatment. Out of these, contempt has been found to be the greatest predictor of divorce.
"Although these are very negative experiences and worrying signs, in themselves they don't have to signal the end of the relationship unless they don't change," Shaw says.
"With new ways of looking at issues and bridging the divide created by poor communication and conflict resolution, you can take the heat out and build enough of a bridge to see what really is between you."
Shaw says seeing a professional counsellor can help break the negative cycle - even agreeing to an appointment and going together is the start of a new approach.
"Ultimately you have to ask yourself: if the trouble between us could change, do I still love, trust and respect my partner? Is there still something important between us?
"You need to have a reason to do the work because it won't always be comfortable or easy."
Eight warning signs your relationship is over
You raise your concerns and they are dismissed, minimised, denied or ridiculed
You know things have been difficult for a considerable period and neither of you is raising the subject
Difficulties (lack of sex, increased arguing, little emotional intimacy) can no longer be put down to a bad patch
You are caught in a repetitive loop when you discuss things, which plays out pretty much the same every time you start to talk
Other people who know you well comment that you seem miserable or that as a couple you don't look happy
You are scared by what is happening at home. You are worried about what the children are seeing, hearing, experiencing
You are not confident you can change your own negative behaviour, let alone influence your partner to change
You can't remember when you were last consistently happy as a couple. Or if you can, it is a distant memory
