I’m not sure I can help much but I can totally relate so will say you are deffo not alone.
My partner is very similar although we haven’t been together so long. Recently the lies have been around me telling him he can’t borrow money and then finding out he’s borrowed it elsewhere and got in some really sticky situations.
I’m missing the person I met who was funny , outgoing and kind. He is now currently depressed and sleeping all day and last night said he wanted to die (again). Just when I think he’s doing better, something new comes out the woodwork. I know I need to cut my losses or he will drag my very successful life down. And I’m at the point where it’s him or me – and I choose me. I’m also desperate to help him. It’s really hard so I feel for your situation xx