Forgiveness requires one person.
It’s an inside job.
It’s the work you need to do to find the peace, healing and love that allows you to move on and move forward without the attachment to the other person through the hurt, pain and offense they may have caused.
So that when that person comes to mind, there is no sting, no hurt, no anger….
You are free.
Relationships require two people.
A healthy relationship is the exchange of respect, love and commitment between two people.
So, that means that you can forgive someone and still not choose to move forward in a relationship with them.
If someone isn’t owning their part,
Or showing changed behavior
Or committing to be different in the future
It would be unhealthy for you 
To move forward with them.
For example: if your spouse cheats on you, it’s your responsibility and journey to forgive if you truly want to be free.
And if that person doesn’t own their part,  commit to fidelity in the future, and work to rebuild the trust then it would be unhealthy to stay, even if you’ve forgiven that person.
Or say your kid is on the playground and some other kid, named Harold, comes and hits him over the head.  Your kid has to forgive and heal in order to be free on the inside.  But if Harold goes around hitting other kids and doesn’t change his ways and everyone says, “Oh well, you know… That’s just Harold” and they they are willing to make excuses for his bad behavior — you are not required or obligated to play with him.
You can forgive Harold, but you’d be the fool for hanging around him.
Unless you have a thing for being hit over the head…
Forgiveness and relationships.
You don’t need to be in a relationship with someone unhealthy to prove you’ve forgiven them.
If someone doesn’t  value you, honor you or respect you, why would you spend your time with them
Unless you don’t value, honor or respect yourself either?
Loving yourself means being free to stay and free to leave.
Forgiveness means you’re free in your heart.
The goal is love.
Being loving includes forgiving, yes, 
But sometimes, it also means
Walking away.
— Stacey Robbins