I would like some advise re taking holy communion again. But I am separated and live with someone else. How do I stand ??
I have some bad news for you - your standing is not too good.
The term “separated” might mean different things. If you were married previously then this marriage would need to be annulled. This process might be simple or problematic, depending on the circumstances of this original marriage (rule of thumb: it is usually simple if this marriage was not conducted in a Catholic ceremony, and is problematic if it was). You should speak to a priest about the specific circumstances.
If you are “living with someone,” without benefit of marriage (assuming this means you share a bed and everything that goes along with it), regardless of your past circumstances, you are willfully living in a state of mortal sin. This, in itself, precludes you from receiving Holy Communion.
If you have a previous marriage that has valid grounds to be annulled (and you seek and obtain this annulment), and you Sacramentally marry the person with whom you are now living with (and go to Confession, as necessary), then you have returned yourself to a state of Grace and may fully participate in the Sacramental life of the Church.
At any rate, you should speak to a priest about this. He can advise you in a more specific manner.