Is this something to break up over??

So my bfs uncle is dating a woman who has custody of her nieces. Well one is my bfs aha and goes to the same college. 2 summers ago they were on vacation as a family. I was moving into college and honestly was so focused on my stuff that I didn’t care or question what he was doing. I figured he’s on vacation his parents are there I’m fine. He’s a super great guy, close with family and all. Definitely not the type to cheat, I’m his 1st gf too. Well long story short I hear some things I don’t like from him and his parents how they were hanging out and his parents were joking that they kissed and all. Well it bothered me but my bf and I were just starting long distance so I was kinda like whatever since I didn’t think we would last as long distance. Well I told him how I don’t like her, saw texts a little later with them sounding flirty and put an end to it. Well Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> I see he liked a picture of her on Facebook, her bathing suit barely covers her boobs and the picture is from 7 months ago. So with my suspicion I go on his fb (he knows my passwords) and see his search history it’s gone! So I’m like that’s weird, then I see what time he liked the picture of course it’s the same time that he was supposed to be talking to his parents about booking a plane ticket to come see me for nye. But instead of talking to me he’s on fb scrolling through this girls pictures? So I told him today to tell me the truth since I knew something was up. Well I found out more than I assumed since his parents had his uncle and his gf come over for Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> and the nieces were there! Well I barely talked to him on Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> since I let him be with his family, I went to mass and he was supposed to call me after but he never did, so was he too busy talking to her? Like I said he’s a good guy but wtf did he not tell me that night “hey Ik you don’t like her but she will be here from Xmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">eve</a>”. Instead of not telling me and me having to find out?! He also lied and said that she had him search a pcuture of her house and that’s when he accidentally liked the picture but thats not true since he liked it in the afternoon. I know he’s not physically cheating but is their a word for this? I think what hurts me too about the picture is this girl has the perfect body and here I am🤷🏼‍♀️ we’ve been dating for 4 years I just never have liked this girl and honestly don’t trust his parents intentions. I was gonna have him just block her but now I guess every family event I can be worried that she will be there...what do I do? How do I make him realize that this bothers me? He keeps saying he did nothing wrong but what if I just let it go what more would happen. Please help😢 we are long distance but see each other about twice a month. I spent the holidays with my family so that’s why iw asnt there