It's one of the most defining tenants, laws, and guiding principles in Christian faith. Love thy neighbor as you would love yourself. It's never an easy situation but it's also one that shouldn't be. Christ didn't come to give us gifts without a little sacrifice. Certainly, loving those that wrong you is most likely the hardest thing you will ever have to do.
For myself, love thy neighbor or love ones enemies is the single hardest piece of being Christian for me. Certainly the law has been around for thousands of years;
You shall not hate your brother in your heart, but reprove him openly, lest you have sin over him. Do not seek revenge, neither should you be mindful of the injury of your fellow citizens. You shall love your friend as yourself. I am the Lord. -- Leviticus 19:17-18
This old testament reference highlights that we as Christians shouldn't even THINK about hatred for another person. Sure that's hard but as people we can usually tuck away that hatred pretty deep, so deep we can even fool ourselves on occasion. Of course the second part is the hardest for me -- do not seek revenge. Ouch. Yes it's easy to go through the platitudes and pretend that such-in-such didn't hurt us. Heck we may even pray for them (or at least pray that their guardian angle sucker punches them in their sleep) but no revenge? No backlash? That's actually the hardest for me. I'm really really bad about harboring hatred, scheming and smashing my enemy as if they were an insect. You can win the battle but I will always win the war. This is what I have got to reteach myself and thankfully I've started that road.
You have heard that it was said: ‘An eye for an eye, and a tooth for a tooth.’ But I say to you, do not resist one who is evil, but if anyone will have struck you on your right cheek, offer to him the other also. -- Matthew 5:38-39
I've recently started to put conflicts that I'd normally feed like a poison tree down; dead stop. I've stopped scheming, stopped with all that poison and given in to trust totally in Him. This is a huge step and one that I'm more than hesitant about on a daily basis. I have serious trust issues in general much less when individuals give me pause. However, I had a moment where I heard that soft voice encourage me to let him handle things. So in one of the biggest leaps of faith I've ever had I did just that. I gave it all to God. Sure the hatred and animosity is still there. I'm working on it but I trust that the Lord will make things right.
I give you a new commandment: Love one another. Just as I have loved you, so also must you love one another. -- John 13:34
So if I can offer a piece of advice from a re-Christian to the rest of the flock or even those who are struggling with hate tainted relationships. Obey the commandments; do your best to obey these. Love like you are supposed to even when you think no one is looking (someone always is). Love like you are Christ himself. What's the worst that will happen? You'll end up hurt, broken and upset. Likely no different than if you'd proceeded with your hatred or scheming. Let it go. Drop all those things you've been harboring and in those empty arms embrace His love.