My†unbelieving husband and I have been separated for the last two years, but we have remained intimate throughout this time. However, I am now certain he has†a girlfriend and continues to want to be intimate with me. Should I stop sleeping with him, or am I required to continue on because we are still married? Is it wrong to still want to be with him? I'm very confused about the subject and just want to follow God's will.
I would suggest telling your husband that he needs to make up his mind. You would like to have him back living with you, but you are not going to play the role of one of his several mistresses. It is reasonable to tell your husband that you will not be having sex with him while he is committing adultery.
Separation is a concept that is not found in biblical times. Back then you were either married and had a home together or you were put away or left, which we call "divorced" today. The intention of a separation is to give a couple to work out their differences without resorting to a divorce, but it appears that you and your husband are drifting further apart instead of coming together.