You might want to think long and hard if this is the right mate for you. It does sound like your boyfriend is being close minded and inconsiderate. You regularly go to restaurants where meat is served and find something to eat and don’t make a big deal of it. You do that because you are regarding his feelings. He hasn’t done the same for you. Try to have a nice chat with him and explain to him that being a vegetarian is very important to you and you don’t expect him to become a vegetarian, but you also think it’s important for him to be willing to meet you half way (meaning occasionally dining at restaurants where your diet is better accomodated). Remind him that eating vegetables will never violate his ethical beliefs, but eating meat likely would compromise your beliefs.
There are plenty of things to eat that are normal “American” food that do not contain meat: macaroni and cheese, spaghetti marinara, bean burritos, cheese or vegetable lasagne, falafel, stuffed grape leaves, cheese enchiladas, tostadas, grilled cheese sandwiches, mushroom pizza. There’s also lots of vegetarian versions of meat filled dishes that he could at least try every now and then. Go online and find a list of 20 restaurants where you think you and he could go together and be satisfied and present them to him as places that you would like to start going, maybe every 5th time. Tell him that you won’t force him, but make it clear that it’s important for you to feel like you are equally regarded in the relationship. Then it’s up to you to figure out if you can wait awhile for him to start being more respectful or not.
My best friend’s boyfriend was a strict meat and potatoes guy for the first 2 years of their relationship. She never bitched at him, but showed him by example how good a vegetarian diet can be (health wise and taste wise). He eventually got curious, educated himself and became a vegetarian. I wouldn’t expect that transformation, but if he isn’t even willing to meet you half way with the restaurant thing, then you should consider if this guy is a good match for you.