I'm 31 and have been/am currently going through a similar situation. I had a lot of problems trusting my boyfriend at the beginning of our relationship and it took a long time for me to trust him due to issues hanging over from my last relationship (long story). How long have you two been together? If its towards the beginning of your relationship it can take time to develop trust.
The reason that I say I'm currently going through it is that my boyfriend recently cheated on me. We've decided to work through it but I'm starting to develop anxiety again when he goes places without me. If I happen to message him and he doesn't respond quickly that's starting to bother me as well. I know its going to take time to get back to where I trust him again but for right now its a pain. Just wanted to let you know that you're not alone.