What would you do?

I started dating my current girlfriend, ill call her Jane for privacy sake, four months ago. Jane was two weeks out of a relationship with her ex fiance of 4 1/2 years. Jane's ex broke up with her because she confessed she wants to be polyamorous and she knew Jane had no desire to have that kind of relationship so without giving Jane a choice to be poly with her they broke up and they resolved to just being best friends. I expressed my concerns for her emotional and mental health, 2 weeks doesn't seem long enough for someone to digest a breakup, to heal, and to prepare to be emotionally available for someone new. Jane assured me that the emotional dynamics of their relationship had changed long ago without her realizing and she herself was surprised at how easy it was to transition right into a friends only relationship with her ex. At the same time it seems like there was no anger or hurt from Jane towards the ex, no real life separation, just jumped right into friends and while that might be possible for them to do its extremely difficult to fathom anyone could be that emotionally resilient and mature.
I didn't ask many questions about the dynamics of their friendship until a few months into our relationship, I didn't want to be intrusive and honestly I didn't feel it was my place to ask questions at first, but the more emotionally involved I became I knew I needed to know things about the nature of their relationship or I would stay in my head about it. Jane tells me what she does daily and vice versa, not out of obligation, but for casual conversation and to share our lives with each other. I could always tell when she was hanging out with her ex because that's the only time she wouldn't share that she had plans and wouldn't mention her name, I just knew when she used "we" or "us" while describing her activity. I finally asked because she avoided saying things and I need open honest transparency for this situation to work for me. I asked and she told me basically they talk daily, morning until night, see each other a few times a week, and Jane's ex has stayed the night at her house a couple times since we have been together and she says her ex slept on the couch. I was floored that she hadn't told me and I explained that without disclosure about her staying the night she left room for doubt. I told her I wasn't angry, but I was hurt that she didn't tell me out of respect.
I asked if their level of intimacy has changed. Are they still the exact same minus living together and having sex? I told her I'm not investing everything into someone and only getting half of an investment back because she's busy meeting the emotional needs of someone else. I explained that I will not ask her to break contact or end her friendship, but if I feel like our intimacy takes a back seat to someone else's or if this becomes an unhealthy situation for me then I'll remove myself. Jane told me of a girl she dated years ago who was also friends with her ex and they stayed the night together and that it was too much and too weird for Jane so she ended that relationship. I used that story as a reference when I asked her to be conscious of what she is asking me to accept.
This may seem petty and I honestly can't believe I'm gonna bring it up, but I've been dwelling on it so I'll just say it. Jane got Disney Plus a couple months back when it came out, and for months it has only been her profile. While Jane was at my house she added me to her Disney and made me a profile we picked out my picture and I thought it was incredibly sweet. The next day she hung out with her ex and after she left I went to Jane's house for dinner. While at her home Jane jokingly made mention that her ex said she was a little worried that their animals would love me more because I spend so much time there and that she understands why folks get jealous of step parents. The next day I went to watch something on Disney and noticed that her ex now has a profile on the app too. I waited days and days to bring it up because Jane has been having a hard time at work and I didn't want to make it a big deal. I asked last night if her ex had said something about me being on her Disney, I had to ask I couldn't let it occupy anymore of my thoughts. She said no that she made her a profile and asked if I was upset. I said, "not really just noticed after months of you having the app and it only being you on there you added me then the next day you added her too and that is the day she mentioned your animals and jealousy, I was wondering so I asked," she said it just happened that way, she didn't want junk in her feed when other people watched.
I honestly don't know what to do. I want so bad to be "cool" and accepting, but I don't know if I can be as cool and as accepting as I need to be for this situation. I beat myself up a bunch for feeling any doubt in Jane, but she said she has purposely neglected to tell me things because she knew I would be uncomfortable or because she didn't want me to be stand offish and it hurt her feelings, I really don't like her reasoning behind her inability to be transparent with me previously. She has assured me she will be upfront going forward. Jane is literally one of the best humans ive met, she has a huge heart, funny, intelligent, and ive never been treated so kindly by a significant other. I fear that if she doesn't create boundries with her recent ex or change the dynamics of their relationship and actually consider her future with me before her past then I won't be able to continue this relationship and that will hurt me. I don't know what to do or how to approach any of this.