Does Bd’s girlfriend deserve to know about me and his unborn child?

She should know

While I'm not saying she doesn't deserve to know, what are you hoping will happen from you telling her?

Do you want them to break up? Are you telling her to try 'get back' at him? How would you feel if she genuinely doesn't care? Is this something that you need to put your energy into right now?

She’s gonna find out. He can’t hide a baby forever. I wouldn’t tell her, personally, because people are crazy and you just never know how she’ll react or if she’ll even try to blame you. I just wouldn’t want to invite any drama during my pregnancy.
I’d keep telling him to tell her though. That’s his responsibility but he’s a liar and cheat

Yes tell to her

If he didn't lie to you then he is saying you knew about her and his relationship? And If he isn't lying to her then I guess she already knows you are pregnant? Sending her a little message wouldn't be a suprise then...

If it was me I would want to know

Everyone deserves to know the truth and what they do with that information is their choice moving forward.

The only thing that would stop me is the drama to my life

Its a lot of drama but at the same time - you could be doing her a favour in the sense that she's getting out of relationship that didn't work and straight into one that already doomed .. id tell her but not to spite him, to give her the option to do better before becoming truly invested