Emotional cheating with multiple women.

Hi all,

I recently found out my partner M, (38) has been sending loads of inappropriate messages to various girls both on Whatsapp/Instagram. It's worth noting we had been trialing the idea of an open relationship, with some hesitancy my side, in that he was more than happy for me to sleep with whoever I wanted, and I was happy for him to sleep with certain people that fulfilled his kink that I couldn't, as long as I knew about it beforehand and they weren't a previous fling.

I (F,35) started becoming suspicious as I kept getting suggested Instagram accounts of girls he follows - every time I clicked through he would be liking their pictures, but I had no idea who they were so not female friends I knew of. As we were about to make things official I thought he had hooked up with someone he had a previous fling with, I asked and he said no.

Fast forward 6 months, (I've now uprooted my life and been living with him for a couple months). Unfortunately I went down his messages and was right, he had hooked up with them. And for two months following that before he eventually told her that he was 'seeing' someone (I was his gf and just about to move in with him at this point), he had been having inappropriate sexual conversations with her - including discussing aspects of our sex life. However I ended up finding so much more. Some as simple as just messaging girls that they were fit or hot on instagram, but some was accepting nudes from girls and even encouraging it and then found two girls he'd messaged about hooking up that I hadn't been made aware of - in fact had no idea. So it now looked like there was an intention to do things behind my back.

I had hooked up with a few people but he was aware of all of these and had even encouraged it. I feel completely hurt than all my boundaries have been crossed about keeping everything in the open, no ex flings etc. I confronted him and he said he was depressed and had been using these girls for validation and seeking dopamine and would never have gone through with it. He says he loves me and wants to go to therapy to work through this and seems genuinely remorseful but I am so hurt about all these conversations that have been happening behind my back.

Is this something you would be able to forgive? I feel like I would never trust him again but it plays on my mind that maybe lines have got blurred with the openness. However I do feel I have been really clear on what my boundaries were.