TheUF - Changing gears - Dropping the rope?

[theUF]

Been pretty quite on my thread lately, been journaling mostly, but I could use some advice right now.

I've been thinking about the possible outcomes of my sitch. Mostly how I would react to them.

One possible outcome is she finds a new partner, I'm being realistic and know that this might be an outcome. I've never been through this before though (serious long-term-R with children) and here is were I struggle :

*She finds a random new partner.
I'll have to be ok with it. Be civil. Friendly. Take it as a man. She is her own person, making her own choices. Hopefully it would be someone respectable. I think I could handle this pretty well, considering.

*She comes together with the guy she was flirting with(OM).
Don't know what to do. I don't know if I can be OK with this. I don't know if I can "support" that.

1.He tries to cheat on his GF with the mother of my child. Knowing our plans for the future etc.

2.He admits fighting with his GF, but is dependent on her b/c he can't afford his own place to live, bearly has enough money for food. He doesn't have a good salary to start with, and he takes time of from work just b/c he doesn't feel like working.

So he is not hard-working, doesn't earn good, isn't faithful, fights alot. The kind of guy I couldn't respect to start with. (I have a non-blood-related family member who acts this way and my eX hated him for being that way. Go figure huh)

IF this happens, how can I ever act as if it doesn't bother me? I don't want that influence on my child, but yet I understand it is her choice to make.
I want to be an adult about all of this and I know I'm looking too far ahead, but this point I struggle with.
How would you guys handle it?