Can i trust him?

Me and my boyfriend have been together 3 years and have a 8 week old daughter together. In a few weeks he is going to amsterdam with a few friends and ive been worrying about it for a while now because he kissed another girl when i was 20weeks pregnant and ive never fully got over it. I feel fat and unattractive after having my baby and tore pretty badly so we are only just getting somewhat of a sexlife back. Im just worried because amsterdam is known for its prostitutes and hes known to make bad decisions when drunk. Ive told him my fears and he tells me therea no reason to feel this way and i would never tell him not to go