No sex

I have a very good friend of mine, and for the past maybe year it seems like her relationship is on the rocks, she says they have gone from sexing like rabbits to no sex for months, last year she found put he was cheating, they worked things out got back together , but there's still no sex for them, I feel bad for her because she really really loves him, she tries everything to get him aroused and nothing gets him, I need some advice to give to her ladies