Platy Fight!

Last night I saw 2 of my platys getting a bit aggressive with each other, didn't think much of it.
All I thought was the female wanted to be alone and she was nudging the male away repeatedly when he kept coming back.

Checked my fish this morning as I do, checking if everyone is alive...

Back from work, turn on the lights and straight away I spot the blue platy male with a wound, next to him was the female red tuxedo platy with bruising on the tip of her nose...

They were swimming around together, I assume they are companions as they have been together since the start and are swimming together most the time.

Is this just a lovers tiff?
What should I do?

Here is a picture I attempted to take of the wound, not very clear but as you probably know it can be difficult...

In my experience (only a year, but hey )  I don't think many females like to get penetrated.
 
I'm still talking about fish
 
I think sometimes it can be a temporary thing.  I don't think platies are like swans etc where they mate for life

I do think that of it keeps on going, you might have to separate them.