How do you trust someone that made you feel devalued / unvalued?

It's not always smarter to just walk away but sometimes a pattern is a pattern and they do continue over time. I believe he really needs to figure out for himself why he is doing these things and what he may need for himself and relationships in general to feel ok. I'm not saying that people will always continue their cheating behaviors but if they have a track record there are often circumstances within the individual that causes them to act out in this way. If they don't deal with things now, they will be more likely to continue their behaviors. Remorse or feeling bad about an action that has occurred is most likely not enough for him to change his behavior.

When trust is broken it is a very difficult thing to repair in a relationship and often takes time. It can be done, but for it to be productive a lot of effort has to be committed. Many partners who cheat want trust to be reestablished quickly and become upset when their partners are not "over it" but this is rarely the case. There is a right way to go about rebuilding and John Gottman believes that a new relationship has to be established after an affair as the old way has to be cast out and a new beginning can occur. In this model, they believe that couples therapy is the best practice but that often the partner who has suffered the break in trust may be experiencing post traumatic stress disorder in which rumination is a part as the individual re-experiences in their mind what they know occurred or what they envision or think occurred. I feel that this truly takes both individual and couples therapy to repair. You need to find a safe place to heal from this fracture in your relationship and be able to do it in your own time. Trauma work is typically helpful in this circumstance and as I previously stated, betrayal can be experienced as a trauma and this may need to be processed before you can be open to trust again.