I have the occasional meat-free red day. I have fruit for breakfast every day and often veg soup, ryvita (HexB) and cheese (HexA) for lunch so it could be red or green, even if scrambled egg, mushroom and tomato and fruit and yoghurt were had for breakfast followed by a cauldron of soup, salad, omelette and a cheese and onion sandwich for lunch!
My OH wouldn't touch Quorn with a bargepole, but I don't find it too hard to cater for us both. Example red dinners:
Quorn sausages (meat sausages for him) with butternut squash mash
Fish pie with carrot and swede topping
Roast butternut squash (or courgette / aubergine / beef tomatoes)stuffed with roast veg and feta cheese
Fish and chips (HexB for potatoes - not too stingy a portion either)
Quorn bolognaise (make a beef bolognaise for OH, all the same veg, just an extra pan to wash!) with HexA pasta (35g dry weight - not a lot IMO)
HexB jacket potato with tuna, spring onion, peppers, chopped egg
Prawn and veg stirfy
Tuna steak with ratatouille
Veggie omelette (can make him a ham one)
Sometimes I do a portion of meat on the side, so we might both have roast veg and couscous, but he'll have a big fat steak on the side, or I'll have egg, beans and chips and he'll have bacon, egg, beans and chips... on green days of course.
If he's not happy with that, show him where the kitchen is