Okay, i am not sure what to advise about this. Yes, DBing says that we need to GAL and be mysterious. Which i agree with. But, i don't think that it means we should try to make our spouses jealous and let them think that we are involved with someone else...you saw where that got you when you told your H that you had been interested in someone else. I don't want to be harsh, so i apologize if it sounds like i am. I think the whole point of GAL is not to make our spouses jealous, but to make us more appealing, both to ourselves and to our spouses. By GAL, we are giving ourselves opportunities to get out and not think about our sitches, which really does no good for anybody. And, it also makes us more intriguing to our spouses...we have to show them a side of us that is fun, to make them realize what they are missing. But, i think to try to make them jealous is a dangerous game that could backfire.
I think you should let it go, unless he brings it up again. If he asks, tell him who was in the car. You don't want to do anything that will turn him off and think that there is no chance for reconciliation. And, you don't want to send him closer to the ow. By GAL, you are doing something for yourself, to get yourself out of the doldrums. It is to make you feel better, which in turn will make you more appealing to your spouse. So, just be careful about trying to make him jealous.
Right now, you have to focus on yourself. Don't talk about the R with your H. Whatever interactions you do have with him, make them pleasant. I don't think that he will think "gee, she is so happy, she must be fine without me, so i can leave." You are just reminding him of the good qualities that he fell in love with in the first place. People are attracted to other people who are happy and confident...not those who are whiny and crying and depressed. Let the ow be that person. You can still be loving towards your H without sounding desperate. Does this make sense? I feel like i am rambling. And i hope i didn't offend you at all...totally not my intention, so if i did, i apologize.