My [28F] boyfriend [31M] told his friends he received a happy ending out of insecurity

My boyfriend [31M] and I [28F] have been officially dating for almost 2 years and we had a bit of rocky start to the relationship. I was not very secure around 6 months into the relationship when he said he was going on a boy’a trip overseas. He was constantly reassuring me that he wasn’t going to be unfaithful and no urges to do such a thing to me. He was updating me throughout his entire trip and the communication made me feel reassured. While on the trip, he told me that the boys and him had gone to a massage parlour where he was offered a happy ending during his massage but he objected to it and so there was no happy ending. I did believe him but now almost a year later I find out that he told his boys when asked how the massage was that he did get one. He is adamant that he didn’t get one and lied about it to his mates to fit in. He said he was just feeling insecure as most were single and didn’t want to ruin the mood. He said he is deeply regretful of this and admits he didn’t consider me and how it would make our relationship look. I feel disrespected as his friends knew we were dating at that time so I don’t understand how someone could be so inconsiderate of their partner and lie to friends just to appear cool and it is also making me question if he is being truthful to me or his friends. What should I do in this situation?