Past relationships affecting current relationship

So ive had bad experiences in my past relationships. And that's created trust issues to the extreme for me.

I met my current boyfriend about a year ago and we were friends to best friends to being in a relationship a couple months ago. I really love this guy but I feel like I can't trust him and I've been trying to hard and I'm sure he's not doing anything. I never go through his stuff. I never ask too many questions.

But last night I accidentally looked over to his phone and saw he was talking to the girl he was talking before we met.

Her contact name even had a heart next to it. Soooooooo I don't even know wtf to think or do. Don't wanna jump to conclusions.