Following my boyfriend’s ex on Instagram?

Hi everyone,

So my boyfriend dated a girl for 4 years and she ended up cheating on him and leaving him for a girl (this was about 3-4 years ago). *Not entirely sure if she’s gay now or if she’s bi*

She still texts him every couple months to see how he’s doing and it’s progressively started to bother me. He had previously tried to cut her off/ distance himself but she still texted him a few months later. I’m not opposed to them being friends (he’s respectfully cordial with her) since they dated mostly throughout high school and a year into college. However, I’m more unsure about her intentions especially since she appears to be out her long term relationship now.

My boyfriend and I have been dating for 2 years and I would like to meet his ex if she wants to continue being friends because if she’s in his life then that would subsequently mean she’s in mine too. I know this sounds pretty juvenile but I’m honestly interested in hearing the best way to go about this...

Would it be weird if I followed her on Instagram? I would never want to do anything petty but I’m aware that it might come off that way to her or I may seem jealous. I’m genuinely interested in getting to know her since she’s pretty adamant about staying in my boyfriend’s life—which again, is fine, but I would like to be involved.

Please let me know your thoughts and advice :)