Yes, you have to. I just wrote a hub you can read on "what does your family mean to you." I mention family feuds and turmoil. You don't have to like them, but you do have to love them. I think we all have family members we choose not to really be around or avoid like the plague. But I do believe in 2nd chances, 3rd chances, forever and ever. You must forgive people, no matter what they did, but you dont have to forget.
"Let all bitterness, and wrath, and anger . . . be put away from you, with all malice" (Eph. 4:31)
If interested, you can read the whole page on forgiveness here