If you want to get your boyfriend trust you again, then you should find time to talk to him. Select a quiet place that will only have the two of you so that you can both concentrate and understand each other well.
Simply talk to him concerning this issue. Explain your sincerity about your love for him and him only. Trust is necessary for any good relationship. Also, it is healthy for both of you to be your own individual selves and find common ground to build on. The only way it will work and grow is to have a good foundation; trust.