Curled up together on the sofa, my partner Mark* and I were happily engrossed in a Netflix comedy.It was a rare, peaceful evening. We had opened a bottle of rosé, and were laughing together, when my 24-year-old daughter Lara* suddenly appeared in the living room, in a pair of skimpy pyjamas.She stopped dead when she saw us. ‘Oh,’ she said. ‘I thought he wasn’t here this weekend,’ she said, looking at Mark with open disgust.Mark immediately sat up and pulled away from me. Moments later, he announced that he was tired and went upstairs for an early night.Just like that, our lovely evening was over.Mark isn’t my husband and he isn’t Lara’s father. He is the man I fell in love with 18 months ago and who has shared my Devon home for the past six months – the home where my two adult daughters – Lara and her older sister Heather, 26 – also still live.These are the eggshell situations I now find myself navigating constantly.Mark contributes towards the household bills — considerably more than the girls do – yet he is frequently made to feel like an unwanted guest. My mistake was asking Mark before discussing it properly with Heather and Lara, writes NikkiBlended families involving young children are notoriously complicated. But nobody warns you that trying to blend a family when your children are adults can be even more of a nightmare. Trust me.I had been married for 28 years when I finally asked my ex-husband to leave, after a succession of affairs.Our four daughters – I have another two girls aged 30 and 28 who don’t live at home – were firmly on my side; they’d witnessed enough of their father’s behaviour.I kept the family home and for the next three-and-a-half years, I was on my own. Once the dust had settled, I threw myself back into life, and on a night out with friends I met – and fell in love with – Mark.He’s handsome, warm, funny and affectionate, like me a divorcee. We are compatible in almost every way. We both enjoy sailing and playing tennis and are real foodies who take turns cooking for one another.I introduced him to the girls after four months over a meal, and they all agreed he was lovely and said it was great to see me happy again.After Mark and I had been together for a year, I asked him to move in. He has his own property which he now rents out.My mistake was asking Mark before discussing it properly with Heather and Lara. I assumed they would be delighted for me, but they completely kicked off. We are no longer an entirely vegetarian household either – Mark eats meat, which I don’t have a problem with, but the girls recoil in horror at the sight of a packet of hamThey said I had made a major decision affecting their home without giving them any say in it. At first, I thought they were behaving like spoilt children: it is my house, after all, and they are both adults … if they don’t like it, they can leave.However, I now accept I could have handled it better.Heather and Lara say they no longer feel able to wander around in a towel or come downstairs in their pyjamas.Although our bedroom is en-suite and Mark has never caught either of them unawares – nor would he, he’s been nothing but kind and respectful – they’ve insisted on locks for their bathroom and bedroom doors.We are no longer an entirely vegetarian household either – Mark eats meat, which I don’t have a problem with, but the girls recoil in horror at the sight of a packet of ham.it means that even sharing fridge space has become a territorial battle.Mark also likes a tidy home – my girls can be messy. He’d never order them around, meaning I’m the one left trying to negotiate.Even a Sunday lunch can feel like a diplomatic summit. Mark is a hard worker (he runs his own small engineering business) while Lara sometimes appears to regard employment as an optional extra. She has been working sporadically at festivals for much of this year, and when she returns home ‘utterly exhausted’ she rarely makes it out of bed in time for a 2pm lunch – which I know Mark finds exasperating.Valentine’s Day was another disaster. I wanted to surprise Mark with a romantic meal at home, but neither daughter showed any inclination to go out, meaning Mark and I ended up at the pub.We subsequently booked a week’s spring break for two to Tenerife. Lara automatically assumed she was coming with us and became upset when I explained it was a romantic holiday.To keep the peace, I eventually gave in. She came — and hated every minute of it. It was a nightmare for all three of us.The worst confrontation began over a parcel. Mark had accepted a delivery for Heather and placed it safely beneath the stairs. When she couldn’t find it, she had an enormous hissy fit and accused him of interfering with her things.He ended up spending the night at a friend’s house as the atmosphere was so bad. Heather apologised two days later, but the damage had been done.Heather now has a serious boyfriend, so I suspect she may move out before Christmas. Lara, however, appears steadfastly attached to home.Meanwhile, I am stuck in the middle, trying to keep the peace between the man I love and the daughters I adore. No one is happy – least of all me.I accept that I should have consulted my daughters before Mark moved in and given them time to adjust. But they are adults. Surely my life cannot remain frozen because they still choose to live at home?After spending decades putting my husband and children first, am I really unreasonable to want some happiness of my own?And how do I make my daughters feel comfortable in their childhood home without making Mark feel like an unwelcome intruder?As told to Samantha BrickNames have been changed.