My bf did something behind my back

**english is not my first language**

We have been in a relationship for 3 years we love each other to death we are bestfriend and what happened isn't usual its really frustrating me and i want your opinions ladies if you were in my place!

One month ago my bf told me he is going to hang out with his friend(in the afternoon) i didn't ask him where did he go and he just told me that they were driving by the car and we agreed that we will see each other that night and we did he told me before coming to pick me up that his friend and his other friend(a girl used to be in the same class at school i know her very well she's nice and i dont have any problem with her) are joining and we eated at a restaurant that night normally!

Last week we organized a journey to go to a place a little bit far but it was worth it(it's a big beautiful lake) when we arrived he told me i came here one month ago and i was surprised bcz i didn't know i asked him with who and why u didn't tell me he said:

With my friend (the one who he hang out with) and the girl from his class and another girl (school friend as well i know her too and no probs) he said we were driving and we saw them so they joined us and it was their idea to go there plus they smoked weed😒 he said he felt guilty for not telling me and he wasn't happy for going without me and without my knowledge but he wasn't in his car to leave and didn't tell me directly so i don't get upset but now i'm more fuckin upset and insecure if he can keep this a secret maybe he can do many others thing or he's doing it all the time!!!! Ughhhhhh!!🤦🏼‍♀️ Btw he apologized for not telling me and he know he's in the wrong!

I didn't believe this coincidence and i feel it was planned i feel frustrated when i think he didn't tell me when they were driving there and not even that they joined them and what was the purpose to do all this shit without me i know he have a life and he can hangout without me i don't mind but not by disrespecting and lying at me!!!!

Sorryy if its long and thank you💜