what does "I could do a lot worse. I have done a lot worse." mean?

my guess is that it's a woman evaluating a man she's going on a date with. "I could do a lot worse (than this guy I'm going on a date with)." as in, he might be a bit below her standards, but he's not too far below her standards. so the guy isn't perfect, but it could be much worse. "I have done a lot worse." - she has dated men who were far worse than this guy before.

"I could do worse" (in this context) is an alternative version of the phrase "it could have been worse", which means you accept something less than ideal, because it's better than other, inferior outcomes. For example, when 10-pin bowling. You'd like to get a strike, but you get a spare. "It could have been worse". In saying that "I *have* done worse", they're reflecting on past incidents which were worse than this one, and therefore their current situation isn't *too* terrible. To continue the example, maybe in a previous round you'd missed all the pins entirely. Hitting only some of them now isn't ideal, but it's preferable to your previous performance. --- The term is most often used in the context of a romantic partner, who - whilst not the *ideal* match - is "better than nothing". This is often a politically incorrect description of a person, but regardless, is commonly heard. I am *guessing* that the person is talking about a person. If that's correct, they're basically saying he/she is "better than nothing", and they've had "worse" experiences in the past.

Exactly what it says. You can and have "done worse". That is, you are about to do something unpleasant (or at least, not immediately enjoyable) and you are reminding yourself that you've done something less enjoyable in the past, so this should be easy by comparison. Based on the context, I'm going to guess this is someone about to go on a date. In which case, they are not necessarily looking forward to the date, but they are reminding themselves that they have dated worse people before.