This is a very 'lodge' style fireplace and from what I can see of your furniture you're a more modern type. Maybe whitewash just half of it? Like, just one side of it? Because I think that's what's happened in your inspiration picture, that is more than just whitened grout.

The white grout on the inspiration picture works because there is a lot of white already in the room (ceiling and walls). Also the color of the bricks are much lighter. When this mortar color transferred to your fireplace the bricks will jump out and the white mortar lines will make the fireplace really busy (too much color contrast). Would retiling the fireplace not an option? You can pick a more modern pebble tiles.

I had a friend that had a huge double sided fireplace like yours (only where you could see and access the firebox from both sides. They tried all sorts of things to improve the look and finally had it torn out. That improved the whole look and flow of their house by leaps and bounds. I know it's probably your husband that thinks the fireplace has to stay but removing it can really make a huge difference in your house. I don't know how much it cost for them to have this done. Their fireplace was an even bigger one than yours.

You could hire an artist to paint over the brick. You can show them your inspiration piece so they can see what look you are going for. Artists who paint murals are good options to consider. Ask them if they've done that kind of work before so you can the results they've achieved.

Do you live in Washington state by any chance? The reason I ask is that I think we have the same brick, or very, very similar. There was a Pro who posted something with brick that was also the same. I actually love it, but when I was getting my hair done today talking about our recent major power outage, the gal who does my hair was saying how she had brick like that and painted it as she absolutely hated it. I love mine but she hates hers so I can understand where you're coming from.

I haven't followed your thread--this is the first I've seen of it. What's on the other side of it? Do you have a fireplace there? I'm wondering if you could have the one side framed in and drywalled so you had a regular wall to work with? It would be something you'd have to talk to a contractor about so it looked right...

HI -- I don't understand what your husband sees in this brick ... I think it is ugly . It took my brother in law about two hours to take his bigger fireplace down and haul the brick out and boy what a difference to the room. He said best thing he ever did . You could lighten the grout with some cream or beige latex paint . Wearing a rubber glove , just have a small sponge or a old wash cloth over your finger and go along each grout line .... it is a bit of work but the best way. That might help .

Consider adding a second mantel, preferably matching the other one, to the back of the fireplace and add wood paneling below that with vertical wood trim boards. You could then hang your mirror above that (lose the tilt). You could also add a single wide finished shelving board vertically to the side of the brick fireplace and use that on which to hang family photos or art. The brick your husband loves will still be there but there will be less of it visible for you to see.

If you decide to lighten the mortar, stay within the existing palette - on my monitor, light grey or a pinky beige would both seem to work.