Since the last problem I had with my boyfriend. I have begin to doubt a lot and worry things will go wrong.
I know this will in some way affect our relationship but i can't stop thinking about it.

 It was 5 days ago me and my boyfriend were about to break up because of his ex. She wanted him back.
At first i was willing to let him go and let him be with her if he loves her. But that night i realize
 i can't let him go if she can fight for him so can i.  I saw him that night too and just told him how i
 really felt. He hugged me and said 'I'm sorry for all this. I promise i wont let you go'.So we are back together.

But I'm still worried about his ex and when I'm not with him. I'm still a teenager and my parents are strict on
me going out and that so i can't see him often. So when I'm not with him i worried that his ex will fill in those gaps
and win him back. Because she is more able to be with him and go out late I'm guessing she is a "wild child". The main thing is that I'm afraid I'll loose him all over. I don't want that to happen.

My friend told me i should just ease off and chill 'Go with the flow your still young' he said and 'If he loves you no one can take him from you'. But i mean i really care about this guy and don't want to loose him. But having this feeling of 'not trusting him' as much as i once was really make me enjoy the time we are together a lot less and worry when we are not togheter a lot more.

I don't think this is a healthy relationship. But I don't to let go. What on earth should  I do? Talk to him?
Now I'm in a 'I don't know' situation so hope you can help me.