Once I have forgiven someone who has lied to me REPEATEDLY, does Christ say I still need to trust and associate with them? Honestly, I am still working on the forgiveness, but future trust is a big stumbling block for me right now.

No, you don’t have to trust everyone you’ve forgiven. That could be unwise. God gave us a mind to discern whether someone is trustworthy or not. You’ve done the right thing by forgiving, but that doesn’t mean you have to trust them. As far as associating with them, the Bible says, “If it is possible, as much as depends on you, live peaceably with all men” – Romans 12:18. Note the words, “as much as depends on you”. It’s not always possible to get along with everyone, so it depends on you and how much you’re able to handle. If you think you can have an “arms length” relationship with the person then that’s good. That way, no doors are closed to having a godly influence on them. Keep in mind that forgiveness is often a process. It starts out being willing to forgive and then the feelings come later.