How can I forgive my boyfriend for cheating and lying to me on multiple occasions?
I'm really sorry that you are experiencing this with your boyfriend. It can be hard to strike a balance between caring for yourself and knowing your limits and caring for others. Forgiveness is something that takes time and in this case, changed behaviors. It's hard to forgive someone who is still engaging in the same behaviors that need forgiveness in the first place.
Think of it like this, if this were a physical wound that someone you loved had inflicted on you and it healed or started to heal, but then they came along again and opened it back up over and over again, you wouldn't really be getting anywhere in the healing process and at some point you might have to set some boundaries with them or even walk away eventually. That doesn't mean that you don't forgive them, you can forgive them but not allow that person to be a part of your life.
It sounds like, even though you are questioning if you should leave or not, you want to try to salvage this relationship. If that is the case, you may both need to seek some individual counseling as well as couple's counseling. It might also be a good idea to talk to him about what his plan is to change his actions and what your expectations are of him. You may also both want to explore your attachment styles in relationships. Someone with an avoidant attachment style may be more likely to cheat because they are trying to avoid getting close out of fear. If that is the case, that would need to be worked on in counseling.
Some things to remember while you heal.
1. Your feelings are valid. Let yourself feel them but be careful about how you respond to them. Berating your partner won't help you forgive them and won't make you feel better.
2. Allow yourself to grieve the infidelity and how it has impacted you and your relationship.
3. Make sure that your partner wants to change and wants to work with you on the relationship.
4. Work on being honest and open in your communication with each other and rebuilding your trust.