26M - 25F - Dating help

I’ve been dating my girlfriend for a short time and some things are really bothering me. Early on she told me about a past situation where she was involved with someone who was older (6+ years, when she was 18) and already in a relationship, which continued until he moved away. She didn’t seem to feel much remorse about it, and at the time it happened at her house a place she’s not let me ever visit.

Since we started dating, I’ve noticed some inconsistencies, like saying she’s too tired or sore to do things with me but then doing them with other male friends, and reaching out to an ex out of the blue “to clear guilt.”

I am not sure what to really do. I just want to understand what to do and if I am being too emotional/ looking into things to much?