My first, co-slept from 12 weeks as bf constantly at night; I was going insane, literally. He is still with us in 'our' bed at 3.5.
I have said to hubby - should he go in his own bed? and we offer him his own bed, but my hubby takes the hump, he loves him with us.
My 4 month old has slept happily in her cot by the bed with a couple of quick night feeds. So no need to co-sleep, but, we plan to move her to the family bed once she is 1 years old, as we feel it is safe then, so she does not miss out on the hours and hours of skin to skin cuddles that son has had over the years.
I don't care if or when son/daughter leave the bed through their choice, or because we kick them out - it will be when the time is right.
And, sex life does not suffer, because we have a perfectly good unused single bed in the kids room to use before we go to bed in the family bed!