Sending you an unmumsnetty hug, if that's allowed here. I've been in your situation, suddenly dumped by husband of 12 years. Though I had great friends and family to support me through it, so I can really really sympathise. I'd be hurt too, but try and give him the benefit of the doubt. Difficult, I know.
Trying to think of something you could do to alleviate the pain and loneliness just now. Shopping is always great, I racked up a great deal of debt that way!!! So perhaps best not. Do you have family round about?
Cleaning is good, cathartic, but you've done that. Could you go for a swim?? I always find that quite relaxing. And maybe sit in the sauna/steam room? A local pool wouldn't be too expensive. Though I can understand you might not want to go out, still early days, but a change of scene might help?
What about just lying on the couch watching old movies/DVDs? Something you really like? Preferably not a favourite of the two of you. Make yourself a cup of tea, wee bit of cake or a biscuit? Pull a blanket over you and yes, just wallow in your grief. It's totally allowed.
Run yourself a nice long bath, some bubbles, a candle, a magazine or book. Do things that you enjoy, that will help you relax, look after yourself.
I'm really sorry you are going through this, it's a terrible time, there is no denying that. I can only say what others have said, things will get better. I'm sitting here with my two beautiful wee boys from my second marriage to a wonderful man. Take care of yourself and more hugs.