Ho! Wait one moment. You are NOT ****ed up. You're struggling. There's a big difference. You made it 18 years! That's a huge accomplishment. Have some compassion for yourself.

What went wrong yesterday evening? Howcome "not being up to sex" equaled "not sleeping in the same bed"? Maybe that's something to discuss with your H and MC? You don't state clearly why you felt like cutting, so this is some guessing on my part. But I can imagine (I have zero experience in relationships, so it's again guesswork) you maybe felt rejected or not good enough or disappointed in yourself because you were unable to satisfy your H. This is something to discuss with your MC, and maybe also in individual therapy.

Please be kind to yourself. You deserve it.