When you've woken up next to the same person every day for years - decades even - it's perfectly reasonable to expect some of the sexual fizz to have gone flat.
But if one of you is neurodiverse - with traits of autism or ADHD - there's an even greater chance of the spark going out.
Studies show neurodivergent (ND) women are 60 per cent more likely to be strongly affected by the hormonal chaos that comes with menopause.
Dr Tony Attwood, professor of genetics at Griffith University in Queensland, Australia, and the author of numerous studies and books about autism, says this will inevitably impact your mid-life relationship - both in and out of the bedroom. This could be a revelation for the one in 100 women already diagnosed with autism or ADHD and a potential eye-opener for the many thousands more who are on waiting lists for appointments.
If someone in a couple is neurodiverse - with traits of autism or ADHD - there's a greater chance of the spark going out (picture posed by models)
Karen Doherty (karendohertycoaching.co.uk) is a psychosexual therapist who has been counselling ND people for 15 years and says a huge proportion of her client base presents with intimacy problems in mid-life. 'Menopause exaggerates everything - it will shorten your mood, heighten your sensitivities and escalate your anxieties,' she says.
While many women will be able to mask what they are feeling, those with ADHD or autism may not, since struggling to process emotions are key traits. So, if your sex life isn't as fulfilling as it used to be or there's conflict in the bedroom, could neurodiversity be the cause? We asked experts to identify the tell-tale signs and offer solutions...
No interest in your partner or sex
'Desire discrepancy' - where one partner wants more sex than the other - is the single most common problem affecting mid-life relationships, and neurodiversity exacerbates this.
Professor Attwood explains that autism is associated with having intense interests, and autistic women can develop a strong interest in a prospective partner early in the relationship - deeply focussing on them and committing all their energy to creating a fulfilling sex life. But, he says, 'special interests' often have a 'use by date' which means, over time, that initial passion can fade away.
'Once the autistic partner feels the sexual act has reached peak perfection, they might resist change,' he explains. 'They might even find themselves thinking: 'Why would you want sex when we have enough children?'
Dawn White, a sexologist, counsellor and coach specialising in ND in relationships and intimacy (relationshipliving.co.uk), says she's seen a similar cooling off in women with ADHD if they experienced intense infatuation at the start of a relationship. This cannot be sustained and dwindles into self-imposed 'sexual inertia'.
SOLUTIONS
Make sex an intellectual challenge
Professor Attwood says some autistic women benefit from assigning 'sex' as their new special interest as this allows them to research it and focus on making intimacy mutually fulfilling.
Be open to novelty
Autistic people often find comfort in routine, which can lead to a repetitive sexual repertoire. White recommends exercises such as sharing your particular 'accelerators' (whatever might spark your passion) and 'brakes' (your turn-offs).
'If you have ADHD traits, introducing novelty (sex in the shower,) or kink (bondage or sex toys) can feed the demand for an exciting dopamine hit,' she says.
Hold a sex summit
Autistic people often appreciate straight talking, so White urges finding time to discuss sex. Ask 'what do you think about our sex life right now?' then discuss which aspects you'd both like to keep, introduce and lose.
Too shy to say what you want
No matter how well you know your partner and how in sync you are with each other's feelings, it can be difficult, in the throes of passion, to explain what you like without risk of embarrassment or offence. If you have autism the problem can be heightened.
'Sex signals often rely on non-verbal communication which can prove difficult for the autistic partner,' says Professor Attwood. 'Missing subtle signals can cause misunderstandings, confusion and hurt feelings.'
SOLUTION
Hand signals
Dawn White teaches her clients a technique called 'hand gliding'. Rather than trying to work out the best way to say you don't like something with the implied criticism, simply put your hand on his and 'glide' it away from the 'wrong' area to your preferred place. 'This helps you connect with your body and stops you over-thinking,' she says.
Can't stand intimacy
One common neurodiversity trait is sensory sensitivity which makes you either super sensitive (or conversely particularly insensitive) to smells, tastes, textures, pressure, touch and sounds.
For many, kissing is a key part of foreplay, but it can pose problems for ND people. 'Heightened sensitivity could make kissing - even kissing someone you love - an anxious experience if you find the smell of your partner's perfectly normal breath nauseating,' says Professor Attwood.
Likewise some ND people also find cuddling difficult. He adds: 'An autistic partner may deliberately walk away when their partner is feeling upset, not due to callous indifference, but because they think their partner will appreciate being left alone, as they do.' An autistic adult might recoil at a hug, asking: 'Why would squeezing me make me feel better?'
SOLUTIONS
Kiss and make up
Professor Attwood says it is important to explain your sensitivities, pointing out that any recoiling from touch should never be taken personally.
'You might decide you prefer not to be kissed on the lips,' he says. 'Very often, once the reason behind a behaviour is understood, it no longer presents as confusing or threatening.'
It's also a good idea to check out sensitivity to the lights in the room, the smells of perfume, aftershave or scented candles and the feel of fabrics, such as nightwear or bed sheets.
Reframe romance
Accept your differences. 'If your idea of romance is being in the same room (albeit on separate chairs) reading archaeology textbooks, let your partner know,' says Professor Attwood. 'There is value in celebrating your autism. Don't be a third rate neurotypical - aim to be a first rate neurodivergent instead!'
Struggling to get 'in the zone'
If you're juggling ageing parents, children and are battling a never-ending 'to do' list, it can be hard to get in the mood.
White says arousal can be a big problem if you have the perpetually busy, easily distracted ADHD brain. 'Women with ADHD can struggle to find the focus required to feel sexually excited and to shift other thoughts out of their mind,' she says.
SOLUTION
Sexercises
White recommends breathing exercises and mindfulness techniques to calm busy brains. She also suggests 'warm up' techniques such as sitting down and calmly breathing together in sync. 'This helps you connect as a couple prior to arousal,' she says.
Another trick is keeping your eyes open during sex. Gazing into each other's eyes can be challenging especially if you have ADHD and struggle with focus but as it becomes easier it can break the sexual trance some ND people get into (focusing intently on their own pleasure) which leads them to lose engagement with their partner.
You feel rejected in bed
If you've noticed your sexual connection waning, it's understandable to worry about the health and longevity of your relationship, but Karen Doherty says for those with ADHD or autism, this can trigger 'rejection sensitivity dysphoria'.
The exacerbating impact of hormonal upheaval and stress often leave ND women feeling as if they're on a very short fuse,' she says. 'A simple throwaway comment can result in you feeling criticised and rejected, with your partner walking on eggshells.'
SOLUTION
Trigger awareness
'Honest conversations are crucial as they pave the way for understanding,' says Doherty, who reiterates the importance of recognising your personal triggers for heightened 'emotional dysregulation'. If the autistic person explains their triggers their partner can learn how to adapt behaviour and language.