[OR] Does this situation seem neglectful and wrong or am I being irrational? Attorney and I are very concerned

Here’s the short and sweet of it.

I have a 5 year old daughter.

In February, I caught my (then fiancé) cheating on me. Broke up with her after 8 years. I move out.

Within a WEEK of splitting, she MOVES the dude she cheated on me with into her apartment. And then I find out… my daughter has been sleeping with this new guy since he moved in. She knew this guy for like 2 WEEKS and just moved him in.

And the worst part: she has him babysit my daughter while she works, when she has her. Some dude she BARELY knows. She lies and says her sister babysits but my daughter told me it’s “mommas new boyfriend” who watches her. And she wouldn’t lie about those details. On top of that, she FaceTimed me and I caught the dude in the background, not her sister, watching her.

My attorney thinks this is grossly inappropriate. And I conquer. There’s other details I’m leaving out and I’ve altered a few things slightly to avoid this coming back to me but I’m infuriated and wanting to go for sole custody. She’s prioritizing a relationship over being a responsible mother.

My daughter has been GRIEVING our breakup since we split and she’s very confused why “momma has a new husband so fast”. It’s messing with her head.

There’s other stuff I’m leaving out, that she’s done. But my attorney is confident we will win this.

Just wondering if this dynamic seems normal to anyone and if we are in the wrong. My lawyer says “well it’s not illegal to do what she did, but most judges aren’t going to like it given the totality of the circumstance and combined with additional evidence of neglect”.

My brother thinks that this whole situation “isn’t a big deal” so looking for further input other than my attorneys.

TIA.