Should I tell her husband? He’s deployed

Sooo there’s a 20 year old girl who’s MARRIED who has an obsession with my significant other. We live across the state from her and are expecting our first baby.

My SO and her had a casual hookup a long time ago and he’s 25. She’s always had this obsession with him, even as to going to hook up with his brother.

My SO has told her from the beginning he didn’t see a relationship with her, but he used to talk to her as a “friend” because he didn’t see the need in cutting her completely off.

She married someone who is in the MARINES & DEPLOYED. A couple weeks ago she reached out and messaged my SO saying she was drunk and to come over and stay the night. My SO shows me and tells me he didn’t know what to do.

So a couple weeks later, she tries to send him friend requests on Facebook. Like will she not get the hint?? He’s having a baby also.

I just don’t see it fair to her husband who is supporting her, in the marines, and currently deployed. I have family in the military and so that disrespect bothers me to a whole other level. Especially since she could be doing that to other men as well.

Should I send him an anonymous email? Or leave it alone?

My SO doesn’t see the need for me to do anything and sees it as stupid. He wants me to stay out of it and not let it bother me. So if I message her, she will most likely flip out. And if I message her husband, I wouldn’t tell my husband.

I also don’t want to stress him out or send him into a dark place as he is deployed.