boyfriend sending nudes of myself, threesome etc.

I feel as though my boyfriend takes me for granted. I know this isn't how a boyfriend to be but i'm stuck when it comes to relationships. There's so many things that make me wonder about him but there's just too many to say.
He's never once taken a photo of me just to admire unless it's a nude photo and he's sent it to his friends? over 20 times i'd say (on snapchat and no one has screenshotted it)
We've had a threesome before which i agreed to (with another girl) but i still don't think he should be accepting it either way. when i asked him ahbout at least a foursome with a girl and a boy he wouldn't allow it as he doesn't want me getting with another guy. his standards are very different he will only hang out with me when it suits him. He's embarrassed if the boys know we're together (he is very friend orientated and doesn't want the boys thinking i'm his first option not because he's embarrassed to be with me) He hates my vegan lifestyle and will bag me and make me feel so little about it. Here's more of a summary
he has major double standards, he's unapprecive of what i do for him, very selfish only pays for one meal once a month and that's all he ever buys me. doesn't invite me to anything (i'm also friends i th his friends), doesn't care what i like or what i have to say (infact he tells me to stop right there when he's not bothered caring), insensitive etc.
i'm just so worried about breaking up with him i've known him since year 8 and i've always wanted to be with him and always had high hopes (i am 18) i know he likes me a lot and doesn't want to lose me and it's just his personality but i know it's so wrong to be with someone like that.
I'm so worried how things will turn out without him. i've tried to break up with him before but he convinces me not to and i believe that i'm being silly by doing it. he's really not a bad person he just doesn't know how to handle a relwtionsho