But my last 2 long term relationships are proof enough that the "golden rule" is not an absolute thing.I have known other couples who had sex right away too.So I guess what I want to make you understand is: Don't delay sex just because you think it will make him want to commit to you.
I will discuss this in general terms first before we delve into the subject of sex during the reconnecting phase with your ex.
I got to turn them down too 'cause I wasn't interested in anything more than just a casual relationship.
As I said, if you don't feel comfortable about it, then don't do it. I have in the recent past dated a guy 4-5 times and didn't have sex with him at all.
You need to have that "je ne sais quois" to make him want to pursue you (which is different with every man), and remember it works the other way around too!
Waiting to have sex is only important when you feel it is important. Now in reconciliation, I think, depending on your circumstances (nature of relationship/breakup and your ex's personality/history) sex can help: it recreates bond between you and your man.