I usually cook a pan of pasta sauce (tinned tomato, onion, pepper, courgette and either minced beef or tuna, or sometimes just veggie) on a Monday, my day off. I eat one portion then, and divide the rest up into meals for Tuesday, Wednesday and Thursday, when I get in tired from work - all I have to do is reheat them, and cook pasta.
Friday, I'm either off to see NT or he's coming to me, so I'm more inspired to cook again.
It helps that I'm perfectly happy to eat the same thing 3 or 4 days running.