How do you build trust in your relationship after it’s been broken and forget the past?

This sounds like a tough situation where you have been hurt but you and your boyfriend have made the decision to work through it. Understandably, you are having to navigate how to trust him again as he has hurt you. I can see you love him and would like a future to work out.

I'm sure you are aware of how important trust is within a relationship - since that trust has been broken it sounds like you have been left feeling quite vulnerable and understandably so. A big positive, and an indicator of some level of trust, is that you are both feeling as though you are willing to make it work and are therefore committed to one another. 

The areas that need to be addressed, however, are that boundaries have been massively challenged - physically and emotionally. And this needs to be addressed before you can begin to rebuild. Understanding the whole context of the situation - how your relationship looked before your boyfriend cheated, any other issues in the relationship, your past experiences of betrayal and/or relationships in general can also help you to gain a broader understanding of yourself so that you can save yourself from future potential harm. 

It sounds like you and your boyfriend have talked a lot about things, and communication is going to be the number one thing that will be able to move you forward from this situation. How transparent have you been with your communication to him about your hurt? I would say that it's important to clearly explain honestly how you feel about the situation, how the hurt feels for you, what you need from them in order to start rebuilding the trust again. 

It sounds as though you and your boyfriend are on the same page about wanting to move forward, and presumably you feel he is sincere about this. Does he seem truly regretful about what happened? Make sure that if when you are communicating, if you feel too emotional to talk in a productive way, you remove yourself from the situation until you feel better placed to discuss again. 

To move forward, it's important you able to forgive him fully. Blaming yourself in some way will keep yourself stuck in self-doubt which won't be helpful to you moving on and will also impact on your self-esteem. Again, communication is key here between you. To forgive, it's important that you don't dwell on what happened too much - but this will only begin to happen when the situation has been talked about openly and transparently so that there are no niggling doubts about why it happened/whether it will happen again. 

If you both commit to working hard to move forward, and learn from what happened and what brought you to this point, many couples find they can rebuild and even become stronger.