Relationships in trouble are like illnesses. Sometimes they require systemic treatment, but most of the time a symptomatic approach is necessary.
Your partner has taken to sleeping on the couch and you are sleeping alone. She refuses to come to bed, even when you promise not to rush her into anything. Instead of curing the systemic sleeping on the couch, treat the symptom of sleeping alone. Sleep in the living room with her. Camp out in a sleeping bag, or the other couch. If she says nothing, then get comfortable in your new bedsit. If she says something, answer her: I wanted to understand your desire to sleep in the living room. I must say it makes raiding the fridge so much more easy I don't have to tiptoe down the stairs and wake you.
Scripture to keep in mind
Six things there are, which the Lord hateth, and the seventh his soul detesteth:  Haughty eyes, a lying tongue, hands that shed innocent blood,  A heart that deviseth wicked plots, feet that are swift to run into mischief, A deceitful witness that uttereth lies, and him that soweth discord among brethren.  My son, keep the commandments of thy father, and forsake not the law of thy mother. ***Cf:Douay-Rheims Proverbs 6: 16-20
I declare that I have no intent to acknowledge, distribute or encourage anything contrary to Sacred Scripture, Sacred Tradition and the teachings of the Roman Catholic Church and the Apostolic See. I submit myself and all the contents of this blog to the judgment of the Church.