I had sex with my sister and now we are having a full-on relationship

DEAR DEIDRE: I’VE had sex with my sister. I knew it was wrong but it felt really good and now we are having a full-on relationship.

I’m 20 and she’s 17 — nearly 18. My dad walked out on my mum when I was one years old and we’ve not heard from him since.

Then mum’s boyfriend moved in and my sister was born soon after, so we don’t have the same dad.

My mum enjoys being with men and there was an endless succession of them throughout my childhood.

A few were OK but most were so creepy I didn’t want to get near, and that’s how my sister felt too. I tried to protect her and it felt like it was just me and her up against the whole world.

When she was 16 she told me that one of mum’s boyfriends was trying it on. I punched him and told him I’d tell the police if I saw him in the house again.

I left home just as soon as I could, although I felt really guilty for leaving my sister alone with mum, who didn’t have a boyfriend at that time. My sister came around to where I am living a few months ago and asked me if she could stay.

She said it was awful at home. Mum’s new bloke is half her age — mum is 38 and he’s 21 — and my sister said it made her feel sick to be around them, plus he kept eyeing her up. I had to say yes.

One night we’d both had a few drinks. She started crying and saying she hated her life.

I gave her a cuddle to make her feel better. Then we kissed and had sex like it was the most natural thing in the world. We’ve been carrying on together now for six months.

She wants us to leave town, set up home somewhere new and have kids together but I know we can’t.

One of my friends found a sexy picture of her on my phone, wearing barely any clothes.

You couldn’t really see her face so I denied it was her but I know we are playing with fire.

DEIDRE SAYS: Please stop now and think this all through. You are breaking the law even if she is your half-sister. If you keep having sex you will surely be found out before long and get into serious trouble.

Not only that but you are risking a pregnancy which would cause immense heartache and massive problems.

I realise you love your sister but this isn’t helping her. In fact you are laying the foundations for huge emotional damage by having a sexual relationship with her.

Tell her that you’ll always be there as her brother but that you must put distance between you for now.

You both need some help so contact The Mix, who are there for under 25s, whatever the problem (, 0808 808 4994).