Hi, I'd like to help you with your question.
It sounds like you feel there is something going on in your relationship with your boyfriend and it's making you feel upset. It sounds as if you suspect he is cheating on you.
Because of your willingness to allow your boyfriend freedom, which is not a bad thing to a certain extent, then he feels free to do whatever he choses. Whatever he is doing now could be innocent or not, but it is hard to tell because you have not set any rules on your own behalf for the relationship in order to establish trust and safety for yourself.
In order to have a good, solid relationship, there needs to be mutual trust. It sounds like your boyfriend is aware of were you are and feels confident that you are in the relationship 100%. However, you do not feel the same about him. This is where things are going bad. There needs to be more accountability on his part, especially since there has been past behavior on his part that could occur again. Your fears are justified based on his past behavior. He needs to be more responsible not only with repairing the past, but with his present behavior.
It seems that you are the sole motivator for this relationship and your fear of "rocking the boat" has gotten in the way of you having rights in this relationship. He has all the choices, you have none. You have given away your power in the relationship to him.
It is up to you to decide how you want to approach this problem. You can stay, change how you approach your relationship, and work out the trust issue. Or you can stay and insist on counseling to help you both work out the problems, or you can leave. If you do leave, do not allow your boyfriend to come back unless the issues are dealt with. Allowing him to come and go and have all the choices in the relationship leaves you open to being hurt. It sounds as if you do not feel you deserve more since he is one of the better relationships you have had. This is not so. Everyone deserves a relationship that has trust and mutual respect, including you.
I hope this has helped you,