Male Guppies Chasing Female Platy

I have two male guppies and 3 female platys. the guppies pay no mind to the two small platys but just recently (they've lived together for 5 weeks now) they suddenly love to chase and harass the large one. It seems as if they're nipping at her sometimes but her fins are not ragged or ripped and other times they are just following her. They always try to stand off face to face with her as she backs up. It is clear she is bothered by them however her fins are not clamped.
Any suggestions for stopping this behavior? I've tried placing the guppies in a net as "time out" and she actually seems to be concerned that they are trapped even though when they are free all she does is run from them. I'm aware male guppies will try to mate with anything so I can't tell if it's just them trying to mate with her or if they are not good to live together. I'm sure they are only trying to mate but will they ever give up? I don't want the platy to become stressed from all the attention and die but I also don't want to get 6 female guppies and have a million babies I would rather just relocate the male guppies if I need to.

I also believe the large platy is pregnant so I REALLY need them to not stress her out.

 

They probably won’t give up, no.

 

would you recommend relocating the guppies into a different tank or adding female guppies?

 

Adding females might not stop them chasing the Swordtail aswell as the female guppies...

 

Do you think they trying to hurt her or mate with her?

Okay thanks for all your help I will most likely remove them especially now that i'm certain she's having babies soon.

 

They’re only trying to mate, but the constant stress invites disease. That’s why with most of the common livebearers you should have several females per male.