We are both in our early to mid 40s and still enjoy each others company, I have always had the usual fantasy of of wanting to see my Girlfriend with another guy but she has always just talked about it. Well last night we had been invited to a relatives 18th birthday party, I didn't want to go but felt we were duty bound to turn up. We showered and dressed to go out and as usual I was finished first and sat on the bed watching as my other half got dressed. She put on her underwear and looked fantastic even though we are both not as young and fit as we once were. She picked up a pair of black tights and I asked her not to put them on , she looked better without them, she listened to me for once and slipped her dress and shoes on and we left. The taxi arrived took us to the club we were meeting at and said that we both looked nice especially "The Lady" I saw my other half blush slightly, something she doesn't normally do. The journey wasn't long and the driver asked if we wanted picking up later, it seemed easier than trying to get a taxi so we said yes and to come back in about 3 hours. The went ok and the drinks flowed and by the time my phone flashed to say the taxi had arrived we were both a little bit worse for wear. We said our goodbyes and the GF decided she needed the loo ..I grabbed her hand pulled her towards me and asked if she would remove her pants for the journey home, me knowing she wouldn't be wearing anything under the dress was a huge turn-on. She said the usual "Do you every think of anything else? Have I ever done it yet ? I thought you would give up asking by now..I laughed as she walked away and I went to the doors to let the taxi driver know we were coming. He asked if we had a good time and judging by the fact I was swaying slightly I think he knew we had fun. Any way the GF arrived and I opened the taxi door for her to get in, as she bent I automatically put my hand on her backside and couldn't feel any pants. as I got in I asked her if she had done as I asked and she smiled and started to laugh a little. The car started its journey round the car park and my hand went straight for her knee. I felt her relax a little so moved my hand up until my fingers touched her pussy, she prefers a bush rather than smooth skin and my fingers flicked through her hair until I found her hole. I heard her moan a little and out of the corner of my eye I noticed the driver adjusting his rear view mirror. "The dirty bastard" I thought and whispered what I had seen him do, she turned her face to me and kissed me. I ran my hand back to her knee and put a slight amount of pressure again I felt her relax as I pushed her legs apart then ran my hand up her thigh so she was exposed form the waist down. I noticed the car slow slightly as he was obviously getting a good eye full.. In the distance we could see blue flashing lights in the road as the taxi came to a stop and I re adjusted her clothing to make her decent again and the driver said we needed to wait while the road was cleared, I said "this better not be on the meter" ... "No No" he insisted as we were good customers, I bet we are I thought. She started kissing me again and as my hand was on her knee again I was shocked to feel her spread her legs and pull up the hem of her dress towards her waist herself, my fingers shot straight where she wanted them as I started finger fucking her. I then felt her flinch and I thought I had hurt her, pulling my fingers out I asked if I had hurt her "no" was her reply I then noticed the taxi driver had his hand on her leg.. she kissed me and held my head and I felt her push herself to the edge of the seat, the driver didn't need asking twice as I felt her start to push back against his fingers and within seconds she was coming, panting loudly, when she had finished he calmly pulled his hand away and started the car, she was still slumped with he fanny lips looking red and glistening I could see he had wiped his fingers on her pussy hair as he pulled out . She pushed back in the seat and adjusted her dress as we pulled up near home, she got out and walked towards the house as I paid the driver and he passed me a card saying he would give her discount rates in the future if we rang him. We went inside and she told me she wanted his cock I told her she would have to make do with mine and told her he offered her discount on future taxi runs, the sex was frantic to say the least. I put the business card on her bedside table and said well he left this for you. She smiled as we fell asleep.