your strategy, analyzed
If you bet 35 numbers, then either one of them hits or it doesn't.
35 out of 37 times (assuming single-0 but no double-0) you will win $35 on the bet you won, but you will lose your other 34 $1 bets. Thus you will come out $1 ahead.
Thus, you win $1 (in the long run) on 35 of every 37 bets.
If one of the other two numbers hits, you lose $35.
Thus, you lose $35 (in the long run) on 2 of every 37 bets.
Thus, out of 37 bets, you will:
win 35, at $1 each, for income of $35
lose 2, at $35 each, for a net loss of $70
Thus, you will lose $35 per 37 spins (on average), using this method, even though you are winning about 95% of your bets.
In particular, your total amount wagered in 37 spins will be 37x$35 = $1295. If you lose $35 for every $1295 wagered, you are losing at a rate of 2.7%, which is exactly as expected for single 0 roulette.