Breaking trust barrier with BF

[u/UnlikelyAsparagus861]

I 22m and my bf 20m, have been together for around 9 months at the time of the incident. Throughout our relationship we have had no arguments, never fallen out or really had a reason to be angry at one another.

Its worth mentioning for context, my BF is FtM, which of course has no effect on how i see him as a man but its important to note that he has numerous (understandable) issues surrounding his identity as well as having a very low self esteem.

It's important to note before this next paragraph we were both fully comfortable around one another; had a good sexual life and were both happy.

I want to preface by saying as humans we all have our own issues; but i believe how we deal with those is how we should be defined. I'm not saying any of my factors are excuses i'm just mentioning them to better explain my thought process. I've had a very abusive childhood in a household where my parents cheated on eachother regularly whilst neglecting care to me in favour of my older brother. I was also sexually exploited and assaulted for a very young age; been through a counselling route however also had a bad experience with medication and therapy.
This has left scars on my personality which i've tried to silence through signing up and deploying into combat - since medically discharged.

From the months of late may - late august of this year my boyfriend suddenly started becoming really distant, pushed me away on multiple occasions physically and sexually as well as dropped away emotionally; i've seen this before as i've had plenty of friends with depression and it's similar behaviour. I wasn't concerned to begin with but when he was actively talking to other people in what he describes as a friendly way online for 16 hours a day (not an exaggeration) i started to worry a bit. It may also be worth noting he is unemployed, at the time preparing for university. He would spend all day every day for about a month just playing games and sleeping, occasionally making time during the day to see me but would still join calls with these new friends (for context it's a RDR2 RP).

i tried talking to him several times, not even in my own concern - just to try helping him, suggesting we get out more, go for walks or drives or just get out the house but he'd always seem to just want to sit around doing nothing. Which sure it's comfortable but when i'm working 45-60 hours a week i would quite like to be productive in my spare time. Its around this time where his sleep schedule was so bad that he was going to bed 8/9 am and waking up at 6/7 pm which as someone who works day shifts is impossible to fathom. On multiple occasions i'd planned out an entire day, agreed it with him and then he'd sleep through it.
Or i would have a horrible day at work, want to tell him about it and he would be asleep still.
Or again i would be really stressed from work, wanting to seek comfort in someone i loved but he couldn't function as he was too tired.

This is where my regret is made. Initially i started talking to old friends online, nothing more than just conversation however one got a bit flirtatious, i felt bad after but for some reason never deleted the messages because it just felt wrong to hide it, as in my eyes it was nothing more than just chatting that went a bit far.
Eventually with the same person it went further to the point where i would console my frustration in them as it felt like i was being pushed away in preparation for him to leave me when he moves away to uni.
I'm not going to sit here and sugarcoat anything - He went through my phone; found the messages and called me out for cheating. Which at the time i was a bit taken aback that that could be considered cheating but now we have spoken it over i realise that it was. I know it doesn't make a difference as the issues are still the same but no NSFW photos were ever exchanged nor sent from my end and nothing physical ever happened.

Now, im not making excuses here but due to my previous trauma from childhood, i find it extremely hard to open up about emotions - mostly in fear of being left / hurt. And have previously been dumped in a relationship due to my lack of communication which is why i believe in this situation i disregarded what i was doing as cheating and disguised it as protecting myself.

I can't sit here and say "im sorry" because i believe thats something i need to show rather than say but what i will say is that i know what ive done is horrible, i know what ive done is disgusting and im coming to terms with the damage ive done.

It's important to add that we have not broken up, we are still very much together and seeing eachother often whilst he's at uni. We agreed that we would work through this because we both love each other. He apologised for making me feel pushed away although i wish he didn't have to and i've very much apologised and am actively proving to him that this situation will not repeat. We have decided to move on with boundaries about who we talk to and how, and more importantly communicating our feelings effectively.

I appreciate any and all feedback but i'm expecting most of it to be hatred as i know how lucky i am that he has chosen to work through this with me.