middle pair: don't wanna fold

[sh58]

Party Poker, $1/$2 NL Hold'em Cash Game, 6 Players
LeggoPoker.com - Hand History Converter

BTN: $271.70
SB: $199.80
BB: $200
UTG: $205.55
sh58 (MP): $203
CO: $377.45

Pre-Flop: 4 5 dealt to sh58 (MP)
UTG folds, <font color="red">sh58 raises to $8</font>, CO folds, BTN calls $8, 2 folds

Flop: ($19) 2 7 5[img]/images/graemlins/heart.gif[/img] (2 Players)
<font color="red">sh58 bets $14</font>, <font color="red">BTN raises to $35</font>, <font color="red">sh58 raises to $100</font>

villan unknown TAG 20/15/2 (datamined hands, can't remember how many, probably 400 or something)

1st orbit at the table, a couple of tight players to my left, so i have been liberal with my opens, have opened Button, CO and now MP, i just knew one of the TAGs was gonna 3bet me or call my raise

i thought this was the sort of boards people love to playback at, but i had to bet to protect my hand and i'm OOP etc.

i was half expecting a raise, but he made such a gay raise i thought he was probably bluffing. didn't really like calling this OOP and didn't want to fold so i thought i had to turn my hand into a bluff (semibluff if he calls/bluff if he shoves).

what would you guys do, cos i don't like bet/3betting with marginal hands very much on these kind of boards, but i couldn't think of a better option.