The actress takes centre stage next week when her case against Pierce Harris (Jonathan Wrather) goes to trial, but Henry said that she did not think Rhona could ever go back to how she was before experiencing the abuse.
Rhona was manipulated, bullied and raped by Pierce while they were together, including an attack on their wedding day, and the character is terrified of facing her ex in court.
Henry said: "It's going to be a slow road to get back to the Rhona she once was.
"I don't think we'll ever see her again because no one can go through what she's been through and be unchanged by it.
"It's a life-changing, awful experience - I think Rhona's probably changed for good."
She added that Rhona was the last person anyone would think of as a victim.
Henry said: "Rhona is historically a very strong woman which is why this storyline has been so fascinating to watch - Rhona isn't a weakling, she's not a pushover, so it's interesting to see how somebody so strong can be brought down.
"She has to look inside herself and find the old Rhona, but it's the worst morning of her life, without question."
She said that she had enjoyed plenty of support from her husband Jeff Hordley, who also stars in the soap as Cain Dingle and is about to head into a central storyline based on his new relationship with vicar Harriet Finch (Katherine Dow Blyton).
Henry said: "Jeff's a sensitive actor and my partner and he knows how seriously I take my work and I know how seriously he takes his.
"It's the little things, really - it's coming home from work and he's made me dinner, or put the washing on, or is playing with the kids while I'm learning lines.
"His time is now and he's got a busy summer ahead so it's my turn to repay the favour.
"That's hopefully the standard marriage situation, whatever your job."
The actress added that she was proud of being part of a big storyline.
She said: "It's always overwhelming how deeply soap can affect people or inspire them.
"It's affirmation that we're doing our jobs well, but it's quite humbling, really.
"I am not an expert on this issue, but I am a human with a big heart and I can recognise that this is awful.
"It's great that soap is current and we need to be telling stories that resonate with people - this seems to have very much done that."
Rhona and Pierce's court battle airs on Emmerdale on ITV from July 24.