I basically caught him cheating

So me and my boyfriend are coming up to 6 months right and it’s nearly both are birthdays , his is a few days before mine, so i planned out a really nice day for him hotel etc etc. I bough lingerie everything to try and make the weekend special. However he recently went on holiday with family and i have a feeling he cheated,he’s been acting weirder with me making excuses for things and dismissing me when i want to try and sort things out. A few days ago he posted this other girl who some of my friends know of and she is not a nice girl.She’s basically a female fuckboy and i have a very bad feeling about her. When i got told my a friend that he posted her i was instantly shocked. Why would be post another girl when he has a girlfriend? I asked him about it and because he can be manipulative and he switched it on to me and made me look crazy. He removed me of social media for the day and wouldn’t answer the phone so i took it as a break up. I cancelled what i was able to as it’s literally next week i’m meant to do this. the day after the removed me i spoke to his friend who helped clear the air and told me that my man and the female fuckboy are apparently “friends”. Me and him resolved everything but now i’m on edge. I see her commenting on his pictures and all and it really fucking pisses me off differently because i know what she’s trying to do. I’m not the type to fight a girl over a boy but i’m really wondering if he’s cheating on me with this girl. She doesn’t even live in our city (I live in london) so i don’t get why she is even bothering. I am starting to think i should just break up with him though and move on and focus on myself or if me and him should just stick it out? Losing him would be like losing my best friend but i need to do what’s myself. (I really need support so any support i will be extremely grateful for). :)

Update:

So things haven’t really improved for me and him but i’m seeing him friday because i’m going to try find out the truth. We’re going for a meal and i’m going to talk to his mum because this our families are close. i don’t think we’ll get back together but i want to tell him how i feel and if it ends it ends on my terms and i will feel a lot better knowing i tried and it is meant to end this way. Letting go of him will be hard because he’s the first boy i feel in love with and lost my virginity too. We had plans for moving in etc but clearly he is too childish for that.

Thank you everyone who commented cause you guys have all helped me with this as my friends won’t let me and him break up they won’t give me guidance at all. Thank you all again so much 💕💕💕💕💕.