love & trust 😔

So ive been with my boyfriend for about 3 1/2 years now and a tear ago i found out he talked to one of my friends who i knew always talked to every guy i dated i found out they were talking he denied it i let it go to find out they were talking and the things they said to each other really hurt im no longer friends with her for good this time its been about a year but it still bothers me my heart feels like its breaking and i want to trust what he says that he will no longer do it again but im so afraid of getting hurt it seems like i kust push him further away we talk about future plans i get excited and then i start to overthink things and i just dont know what to do .. Any advice?