The dilemma I’ve been with my boyfriend for a year and it’s been near perfect, if not for the fact we don’t have sex. It dwindled after three months and I attempted to initiate it – even though it’s not really my character – to no avail. Now it’s not only barely existent but unenjoyable for me as he feels obliged to do it. I’ve always had a high sex drive and at the moment it’s all I think about. I really care about him and feel this is the man I could marry and have children with – he’s voiced several times that this is what he wants, too. I’ve brought the issue up no less than five times now and each time he either changes the subject or blames stress at work. The problem is, he wants me to move in with him, so this has well and truly come to a head. I need to make him see that this is a huge issue for me. I would have considered moving in and seeing how it went, but we don’t live close so this will be a big upheaval. How do I tactfully broach the subject?

Mariella replies Is there a tactful way to say, “Over my dead body?” You have to ask yourself an important question: why would an intelligent, functional, rational, human being expect you to opt for a sexless future with a person who can’t even communicate why they’re unable to engage with you physically?

There are incompatibilities in every relationship that need to be ironed out or tolerated and then there are huge glaring amber warnings. This is one of them. I’ve said it before, but it bears repeating. If you don’t enjoy any sexual chemistry at the start, you haven’t got a hope in hell of igniting it in the future. If three months into your relationship the activity that distances you is a lack of physical desire, then it really raises a question about what you are bonding over. There are relationships of all varieties out there and plenty where the sexual compulsion has long since ebbed. Some people agree to live without sex, others are happy with physical proximity and, very occasionally, couples agree sex is not an issue from the start.

This is an amber warning – a major obstacle to happiness

You don’t fall into any of these categories, yet you say that you have met a man you can envisage marrying and having children with. Aside from the obvious – that sex is an essential part of that latter equation – to be compromising on such a vital element so early on suggests an act of self-harm. That doesn’t mean you and your boyfriend are necessarily wrong for each other, but you’re certainly faced with a major obstacle to future happiness that you don’t seem to yet recognise.

Raising this looming hurdle only five times in a year of dating seems positively restrained to me. I’m surprised it’s not a daily chorus of disappointment. The importance of physical coupling, when you first meet and then later as a form of communion when outside forces seem set on prising you apart, can’t be underestimated. It doesn’t matter if you’re swinging from the chandeliers or slipping into the missionary position – or even doing it because you’re so connected mentally that you’re eager to engage in anything that prolongs that connection.

There are many reasons to engage in sexual activity and not all of them are down to the compulsive alchemy of chemistry. As time passes desire dampens and that’s when you have to work harder to keep sex going as a bonding exercise, if not an expression of wanton lust. If I can generalise for a moment, we women spend way too much of our lives excusing ourselves for presumed misdemeanours, overlooking our own needs and accepting culpability for things that are not our fault. Here you are apologising for the fact that you have no sexual relationship and swearing lifelong allegiance to a near celibate liaison while declaring that you have a high sex drive.

I think there would be immense value for you in pursuing the reason you’re so eager to sign up for life despite the relationship lacking a central ingredient of enormous importance to you. A session with a therapist or counsellor just to work out your own motivations for continuing the relationship would be a natural place to start (visit tavistockrelationships.org and relate.org.uk). Why do you feel a man who can’t respond to a vital and perfectly justifiable need makes sense as a life partner? Physical intimacy is as important in a relationship as all the other things we hold dear, but for women there’s often a deep insecurity about being open about their desire. You have nothing to be ashamed of and every reason to treat this as a major obstacle to your future together, rather than an insignificant detail that you are uncomfortable about expressing. The choices we make are inextricably connected to our influences and experiences in youth and there’s something worrying about the value, or lack of it, that you are ascribing to your own needs.

There’s no question that you need to have this conversation. If you both commit to resolving it, seek help for what is truly a non-negotiable aspect of any budding relationship, then you may have a future together.

If you have a dilemma, send a brief email to mariella.frostrup@observer.co.uk. Follow her on Twitter @mariellaf1