No freezer might be a problem. I also have to cook for one (my hubby is as skinny as a rake but eats everything either deep fried, smothered in butter or wrapped in pastry

).
I don't have a large freezer and also get bored with lots of the same meal but I have found that a lot of the recipes can be halved or quartered (they mostly serve 4) with a bit of practice. Some ideas I use for one person...
- lamb chops or pork chops, fat removed before cooking otherwise I find it too tempting, with new potatoes and lots of free food veg or salad
- steak and SW chips and salad
- when cooking rice for one meal I cook extra and use it the following day in a stir fried rice with whatever bits I fancy like chopped veg, ham or chicken
- tuna and pasta salad
- couscous with roasted veg
- my favourite salad is smoked kippers, new potatoes, beetroot, rocket and chives with a dressing made with horseradish, lemon juice and some crème fraiche
- with lots of willpower I can roast chicken pieces with their skin on and remove it before I eat it (hubby helps to make it and the temptation disappear)
- after
lots of practice and measuring I can now cook pasta for one and love this "risotto" made with orzo pasta ...
fry light/dry fry some chopped onion on a low heat so they soften without burning, stir in 35g dry orzo pasta, make up a fairly concentrated chicken stock with a cube (actually I use TELMA chicken soup mix which I find in the Jewish section of the world food aisle in Sainsburys - lots more flavour) and slowly add it to the dish like you would a risotto - a little at a time, allowing the pasta to soak up the flavour before adding more. You do need to keep stirring because the pasta sticks. When almost done add some frozen peas. I can eat a bowlful of that or serve it as a side with a cut of meat or chicken.
- fillet of fish wrapped in baking paper with a selection of veg like cherry tomatoes, sliced courgettes, olives (if you count the syns), some herbs and a squeeze of lemon, baked in the oven.
Anyway there are some of the ideas I use for one person. Don't know if it helps but good luck. I'll be following this thread to see what ideas other members have because I have the same problem