TL;DR I believe my boyfriend is a flirt and he lies about his true feelings for me
me '18F' and my boyfriend '19M' have been together for about six months now. we are pretty young we just graduated high school together and so far I feel like he's an amazing person and I always think of spending my life with him. he's the first person who actually makes me consider marriage or children. on the flipside, there's some things that I just don't know if i can continue to deal with. I admit i am an anxious and jealous person but i feel as if he brings this side of me out. Whenever he leaves his room or phone i feel the need to search. i know thats a problem in itself and he says i am always searching for something but if i did not find what i was searching for i wouldn't keep looking. for example he's always in constant communication with a bunch of girls and their conversations are flirty, late night phone calls, asking girls if his pictures look good, doing activities with them that we do together, completing them, having an intimate conversations.
I've seen him asking him to be put on with endless other girls on his Instagram. though he claims his friend was on his account. He follows more girls spam pages than he does guys. he doesn't think to block old flings from his past when they text him again as if he gets satisfaction from people wanting him. he has kept a love note that he wrote to a girl stating how she is his first love even though he tells me that she means nothing. and when I bring it up, he insist they're just friends and I have nothing to worry about. Or gives me some extremely perfect and logical explanation for these situations. i'm so confused what if I have a genuine, good guy who just makes mistakes or it I'm with someone who genuinely doesn't care about me and is manipulates me. This all makes me uncomfortable he feels as if i want him to be antisocial or have contact with no one but he doesn't understand it's the way hebut he doesn't understand it's the way he socializes that bothers me not who he socializes with. I dread going on his phone or unlocking it because I know I'll always find something that bothers me and will always get into the cycle where I get upset and he tells me I'm overreacting and says or does whatever he thinks will fix it in the moment.
A few days ago was the most recent time i found something on his phone one of his so-called friends was telling a group chat about how he was trying to get put on while he was dating me. He says that's not true, and that happened way before we met but he couldn't clarify it for me. and he seemed to understand what i was saying. Yet he changed his passcode and claimed it was because he didn't want his mom on his device..Should i
attempt to go through it again? Is this something that can be worked on? And are my feelings valid?