Hello,
I believe, that assuming you don't have an STD, there is no reason to tell anyone anything.
In my opinion: if you love someone, are even seriously dating a person, or even if it's just the first date..why would you want to interject anything about your past relationships?
Here is part of my reasoning:
Although I think that logically, if someone has a high enough emotional IQ...it probably shouldn't matter...relationships aren't always logical...
When you tell someone about your history, I believe that in essence what you are doing is "injecting" "bad energy" into the relationship, if my metaphor makes any sense. Some women, tend to get reallllll funny...when they find out about other women in a man's past. (And by "funny", I mean wacko, vindictive, etc.)
I think it may have something to do with how women think. For instance: I never mentally compare myself to the other men...that my gf's may have dated, because I find no reason to do so...but when women have found pictures of me with other girls...the resulting situation has rarely if ever been good. I think this may have something to do with how the media often conditions women to have a lack of respect for other members of their gender. (not always the case though). This also can manifest major problems, if the woman is not completely self confident.*there are some media campaigns which should be praised such as the "Dove campaign for real beauty"...or whatever it's called.
I think, however...if the woman is self confidant...and sure of your feelings for her, then knock yourself out.
*I also believe that as a gentleman

, it's just not proper to divulge information regarding this topic.
I hope someone on here finds my opinion useful!. - Happy Holidays!!!