[Suicide Junkie]

Which is why you need multi-turn combats.
If you attack on turn 1, and see that you're losing after the turn processes, you can order a retreat on turn 2.

For example, in CB3, I got into a 300 vs 400 ship battle. After letting the turn grind away that night, there was 600 ships left, lots crippled. Either of us could have ordered a full retreat at that point.

I pulled out a handful of weapon-less but still fast ships, my empty carriers and miscellaneous others. The rest of my ships I left there as cannon fodder to help the reinforcements I was bringing.
The other guy seemed to leave all his ships there by choice too. Maybe he thought he was winning, since he had more than me still.
By turn #3, it was too late for him, as his fleet was decimated over a number of combat events, and he only escaped with 10 or 20 ships.