The Clan faces a river decision

[Topflight]

I'm out of town so I don't have the hand history on me. But the hand went like this.

I am dealt KK late mp.

utg limp, I raise, button calls, utg calls.

Flop: Ah Kh 8s

check, I bet, raise, call, I three bet, call, call

Turn: Qc

Check, I bet, call, call

River: the beautiful Th

check, I check, button bets, utg checkraises!! now it's up to me. How easy is this fold?