Looks like there is an argument for every play lol.
I ended up just flat calling, hoping that a spade wouldnt hit on the turn then I could check-raise all in when UTG bets again. Unfortunately, the turn came 4

. I checked it again hoping someone maybe had Q

but it got checked around.
River came a blank, I bet 1/2 the pot and they both folded.
UTG went on to call me an idiot and then left the table. So Im guessing he flopped a set, which is probably right, as the utg limp then call definitely screams pocket pair. Im still torn between raising and calling though. If I raise, he might be scared of the checkraise and fold(unlikely, but it could happen), if I call most of the time a non spade is going to hit that turn, I'll check and he'll pot commit himself with a large bet. I think both plays are about equal..thoughts?
See here's the problem with being OOP and playing passively. You run the risk of losing control of the hand. If a scare card comes and you check...it can check through. You're also giving a set a free card. There are just a ton of things that can happen on the turn that you don't like seeing.
Now I don't think he's going to fold to a checkraise on the flop, granted, but the c/r gives him an opportunity to do so. It's just too suspicious of a play. You probably aren't doing that with one pair type hands. Lead at the flop instead so that you'll get raised, and then you can shove. Now your range, while including the nuts and a set of jacks, also includes AAs, KKs, or AsKd, and there's no way he gets away from his hand. Leading makes this hand that much simpler.
When you flop a monster your reaction can't immediately be to slowplay it and hope someone catches up or hangs himself (but I'd be more in favor of flat calling if you were actually in position). You have to ask yourself what you want from the hand. Here you want to stack sets, two pair combinations, and smaller flushes. You can only do this by playing the flop fast and hard. You also want to charge weaker spades to draw dead. Now if you slowplay you run the risk of shoveling money in when you're the one who's drawing dead - when the board pairs, for instance. Don't be afraid to take a pot down uncontested when you have the nuts. Yeah, it sucks when it happens, but unless you're playing a total idiot then you'll only win big pots off big hands, and you'll only find out if someone's got a big hand by playing back at him.