That relationship relies on lies. Better to kill it, it's not going anywhere.
OP is just afraid to be single.
There is often more involved than just a simple relationahip. Kids from broken homes that get time shared between two toxic parents is just one example. If the domestic relationship is solid in terms of family, financials, career support, socializing/friends, shared interests, etc., then “Killing It” will do more harm than good. I’ve seen too many kids suffer because their fatalistic parents couldn’t figure things out.
And frankly, this idea that cheating is one-sided is just B.S. I know lots of women who do extra-marital romps even though their husband would Gladly have sex with them.
Also, who is cheating on who? If you committed to a marriage which includes a reasonable expectation for sexual fulfillment by both partners, and then sex is later witheld, the lonely spouse is cheated out of their marital dues by the spouse who cheats them from happiness by witholding their vowed promises. Your honour, isn’t the onus on the witholding spouse to explain their actions and make reparations? The spouse who’se life is arbitrarily made unhappy from their partners frigidity is actually just counter-cheating to overcome sex-witholding. So can two cheaters live together happily? Sure, happens all the time. If the other aspects of the relationship work, they are better off than becoming serial divorcees. Of course it would be better if they discuss it, but the social mores and ego hits are two big, so they choose to live a less-than-fairy-tale marriage of don’t ask-don’t tell.
