i dont know how i feel

ive been with my partner for like 2 years and we have a 3 month old son together and his always been really loyal to me but this morning i woke up for our son and he haf a message from a girl on kik but he doesnt have kik so i snooped and i found him talking to a girl saying how she was sexy and he was horny and calling her babe and they had only talked for about 2 hours and im really hurt and dont know what to do 😢