Advice needed!

[Skymum16]

I need some advice..... I found out early on in our relationship that my boyfriend had a dominatrix before me. I felt a bit weird about it but I’m very open so he’s always known he can ask me for anything. He hasn’t seen her since but i basically found out at the time (I looked through his emails), felt really betrayed and he promised never ever to contact her again. I told him if he did that would be the end of us.
Now I know I shouldn’t but I’ve just stalked who he’s recently followed on IG and she’s right at the top! I feel so hurt and insecure. I don’t know what to do. I love him so much, we live together, but I just can’t deal with being lied to and this feels like a huge betrayal.
How can I ask him about it without basically telling him I’ve stalked him?

If he was seeing her before you got together, why did you feel betrayed?

When you say you found out at the time because you went through his emails - wjat was that about?

Hang on, you're spying on him for no actual reason bar your insecurity, and you feel betrayed???
You even say he's not seen her and it sounds like the emails were from before your relationship. You need to focus on yourself rather than him and find a way to make you feel more secure in yourself

You clearly do not trust him is my guess, and so what are the reasons behind it

I looked through his emails after an argument and found out he’d been buying her expensive lingerie for the first few months we were dating, that’s why I felt betrayed. So he promised never to contact her again

Sorry I wrote that in a hurry because I’m at work and just realised it didn’t really make sense. He’s promised me he hasn’t seen her since he met me but he was sending her monthly underwear ‘gifts’ which was what I found out about hence feeling betrayed. Anyway he made me a promise so why on earth would he suddenly start following her on Instagram?
He is a wonderful man who looks after me and my LO so well, I just feel like I’ve lost a lot of trust in him.