One piece of advice, don't claim to be any sort of vegetarian here...semi- or otherwise because someone will be sure to come along and remind you that beef is meat and that vegetarians don't eat meat, and they will insinuate that you don't know what you are talking about. You will get a thorough label adjustment. I guess I just did it to you too. hahha! The truth is though...if you want to eat mostly plants, and pick and choose occasional meats...you are allowed...but there will be many who think you should pin a word on your chest and then live by it. I say don't.
I am a lot like you. I eat meat, but not loads of it. I have both ethical and health concerns about meat, and I am also not huge fan of handling raw meat to cook it. It kinda makes me a bit paranoid and I start cleaning everything. I eat a lot of ground beef too, and since you enjoy that, you should keep it on hand. You can do loads with it. If you want to vary that up a little, you can use ground turkey. It is a lot cheaper.
I also like smoked sausages. They are often horseshoe shaped, or they look like a fat hot dog. Hillshire Farm, Eckrich, Johnsonville, Butterball, etc make them. They are fully cooked and seasoned, and they are very versatile to add to lots of dishes, or you can grill, fry, bake, boil, nuke them. They are made of mixed meat usually, or you can get beef, or pork, or turkey only. My fav way to use these is to cut them into slices on the bias (basically a round coin shape only slanted) and then add them to pasta just before it is done to heat the meat up, drain and add a bag of frozen California mix (carrot, broccoli, cauliflower) or stir fry veggies, and add a jar of your fav pasta sauce. It is a very hearty, easy, and fast meal. You can have it done in the time it takes to cook a pot of pasta.
I don't know if you like beef tenderloin or roast. I love them. Tenderloin is meant to be grilled or broiled...serve it like a steak...with baked potato, etc. Shoulder roast is super easy in a dutch oven or a crock pot. It is slow cooking but easy to prepare. It goes great with veggies that have been cooked with it, like carrots, potatoes, onions, etc. You can shred your leftovers, add barley or noodles, and make a nice soup with it.
Um...you might like beef better if you experiment with doneness. I hate rare meat, it makes me gag. But if it is only very slightly pink, or well done...I love it.
You may or may not find these suitable to your taste. As far as the rest of your inventory, ask your boyfriend and keep his fav items on hand. Then either leave them big so you can pick them out, or serve them to him and leave it out of your food.