I posted this question
about six months ago. As mentioned in my follow-up there, I decided to give a second chance to the fellow I've been dating/living with, who had been flirting with his exes via text message about a year into our relationship.
He was extremely contrite, teary, and adamant that nothing of this sort would happen again. I've kept a close eye on him (yes, including Metafilter-not-approved methods) over the intervening period, and there has been nothing remotely troubling since then. He's let me vent and interrogate him a number of times since March, and if I ask to look at his calls or anything like that he hands over the phone without hesitation.
The problem is, although I have decided to give him a second chance, and I do fully believe he means well and is trying to re-earn my trust, I am having a hard time internally
getting past the betrayal. I do realize that I have it easy compared to many: he didn't actually cheat, there was no serious intention to seek out other relationships, and he has stopped the problem behaviour without complaint. Nevertheless, as a naturally jealous and insecure person, I continue to feel troubled very regularly. It gives me intrusive thoughts, it makes me overreact to really ridiculous false alarms (e.g. if he gets a text, I'm on edge until I see it's his parents or somesuch), and it causes me to seek his reassurance on an abnormally regular basis.
I know this is a really unhealthy mindset and not reflective of our current relationship. I don't think it's my subconscious warning me of anything because I have been jealous and insecure in every relationship, even those without warning signs. It crops up most when I'm tired or stressed, and not based on any external stimulus such as him behaving weirdly (which hasn't happened at all since our talk).
I don't want to just dump him and seek out a different partner, because I will surely still suffer from trust issues and I do feel this guy is a very good match for me overall.
I don't know whether there's any point to therapy, because I already reassure myself that my distorted thinking is causing these negative feelings and I actively try to adjust my thinking. I assume this is what someone administering CBT would do anyway.
I don't like reading forums such as Surviving Infidelity because they actually make me feel more paranoid.
So what can I do, now that I've made the decision to stick this out, to feel safe and comfortable again?