How to mend a disconnected relationship

I have been with my SO for 3 years. We have a one year old and currently a few weeks pregnant with our second. Our relationship is hanging on by a string. I truly believe it can work and be wonderful. I just don't know how to mend it. I have trust issue badly , due to past relationships and a few minor things from this relationship. Where do I start . He's a great guy , he's really is. Amazing father , provider & treats me like a queen. There just a huge disconnect. Where do I start? What are some ideas to help?