RSB-Refugee said:
It sounds like you are resigned to losing at least one out of three games, and in your mind 'he is due'. Don't let that crap, creep into your head. So what if you break even, it wont hurt you. You have to get past the fear of losing, if you want to win.

As it is, this thing is getting in your head. Try to remember he has thoughts running through his head too. If you can figure out what makes him tick, then a solution to your problem, will become evident.
You say "Close sets, he comes out even, winning one set to my two.". I think you meant to say 'playing even, he comes out one game down out of three', there is a huge difference. It sounds to me like you may be a locksmith. Maybe with this guy, you should be playing races, you to 6 and him to 3. With this scenario, he would not feel like you are robbing him and probably be far less likely to bring-up the double-or-nothing option in the first place.
Tracy
It does get into my head. Bugs me a bit that I let up in the last case set. Perhaps you missed the start, but these are handicapped sets, I race to 5, him to 4. And we do usually split sets fairly evenly, me getting the better of it over the long haul, though I can dog the case 9 when it is short and almost straight in (grrrrr).
Tonight for example we played 6 sets, no bets on the first 5. He played from 3pm all day, I came in cold at 11pm, he gets first set 4-2. Then I'm warmed up and next 4 sets go 5-3, 5-0, 5-2, and the last set he offers our "beer match" signalling he is done for the night, last set. I win tonight 5-0. I was playing well, and he had maybe 5 chances at the table each set, 2 were very good safeties, giving him 2-3 long yet legitimate chances to take charge... he did, but dogged a later shot if he didn't get out. The matches he won I cleared most off then dogged it and left him easy outs. This happens. Mostly 2 inning matches on average.
I may be a locksmith... but then I -never- offer to play for money first with anyone, am perfectly happy playing for fun. Once they offer it, I consider my odds, and accept when it seems in my favor. If that be locksmithing, fine, but I'm not out creating these situations with intent to take money, the other guy offers it first in every case. I'm in the 85% range of stronger players around here, and the gambler types like ring 9-ball, and I won't get in the match unless there are 2 weaker players than me out of 5... the room owner is a very strong player and would love nothing more than to entice me into any gambling scenario and take the cheese home... there could be no fair chance there in any 9-ball game, where he only wants to play even or 6-5 at most.
One pocket he is just learning, and has seen me take down a former Japan Open SA player, and lost to me himself... so he is rather shy on trying that game again with me. Who's the locksmith here, where I figure the only fair shake I can get is playing one-pocket, and I better not make one defensive mistake or they can and will run out on me.
As you say, my normal B player match is in my head, and he has thoughts too... and when I execute well, I can shut him down pretty good. Last two nights for him, tonight for me. It is pretty even and there are no hard feelings between us, the stakes are for fun.