Aha! In that case, possibly what you need is a code of honor. Lay down some rules of constructive behavior (I'd recommend studying a variety of historical precedents first, particularly the ways in which they can go wrong... Bushido, Ms. Manners, etc.) and pretend to be the sort of person who thinks that following those rules is the Most Important Thing.

Done correctly, you can stop worrying about the uncertainty of whether some other choice would have had a better outcome, since in any given situation there is only one honorable course of action. Simply calculate what the correct action is, and follow by rote. Under some circumstances honor may compel you to trust someone who most people would not, pass up opportunities for personal gain, dive into a frozen lake to rescue a complete stranger, openly defy the law, or otherwise engage in heroically self-destructive behavior, but it is entirely possible for the gains (from following a calculated strategy, and from other people learning to trust and rely on your consistent behavior) to predominate.

This may be controversial, but I would recommend against keeping an explicit, external record of how honorable or dishonorable your behavior has been. A journal or blog can be useful in other ways, but the plan here is eternal striving toward an ideal, not 3% improvement over last month.

Let's remember that the purpose of this activity is to give to a safe opportunity for you to have social interactions. Hopefully, this will help you be more comfortable with the idea that other people do not interact with you for the purpose of causing you distress. To that extent, beware trivial inconveniences.

Still, losing is no fun - you might not be able to force yourself to keep something that only might be helpful but is not enjoyable. Games have a variety of mechanics for preventing attack the leader mechanics based solely on player reputation.

First, you can anonymize player input. That's what Apples to Apples does. But it is a light party game (not my cup of tea).

Second, you can restrict the player's ability to target specific other players. Dominion works that way - generally, attacks target everyone at the table equally.

Third, you can pick games with much higher complexity. One of my favorite games, Brass, is at least an order of magnitude more complex than a simply game like Monopoly. You are unlikely to find that others target you simply because you are smart and analytical when it's almost a prerequisite to play. In fact, it might be worth some time looking at Boardgamegeek (warning: potential time-sink) to find interesting looking games where your analytic nature is unlikely to make you a target.

I really do think that practice is safe social interactions will provide helpful to you, both because it is providing data to adjust your social predictions and because improving social skills will make you more effective at avoiding unpleasant social interactions.

I've never tried forcing myself to like a game, but why do you think that you need to?

There are very many games in which you win by doing better than other players and you can't really make specific other players do worse. Odds are you'll like some of them.

There's Dominion or Race for the Galaxy. There's trivia games. In general, many games classified as "party games" are good, but not all: Mafia, for example, would be a terrible choice. There's cooperative games like Pandemic.

There's also two-player games (like chess) in which you at least won't have a group teaming up against you, or team games (like spades) in which you'll have (at least) one person on your side.