Unless she has a child with an ex, there is no need to be in constant contact with them. I'm still cool with my recent ex, but we only catch up once every few months.
If she needs to have a her exs around or in her life constantly, I honestly wouldn't bother. Not because she is doing anything, but because you 1) shouldn't have to fight for a place or attention 2) will end up feeling jealous and 3) will probably have sh1t loads of arguments about it and end up miserable.
Talk to her and tell her how you feel. If I am with someone I personally distance myself from guys I know want to be with me intimately. You will know what to do with how she answers your concerns.
Just make sure you stress that it isn't jealousy, but you want and deserve to know where you stand with her.
PS sorry, I don't have a penis, but I thought I would offer my opinion