Emma - I remember replying to one of your posts when you had just found out. This is very much a rollercoaster and you're likely feeling bad because all those emotions are brewing under the surface for you still - it's too much to process at first, so it comes across as more of a sense of uneasiness or anxiety or just feeling 'shitty'. They will come out over time, once the shock wears off and the more you try to fight them the harder they seem to 'yell' at you it seems. This is a grieving process and to heal you will likely find you have to grieve what has happened. Those who try to just move on and not deal with it seem to be referred to on here as 'rugsweeping' on here (I'm relatively new as well). Everyone deals with things differently and this is all so fresh for you, just be good to yourself and accept the emotions as they come to you...it's ok to feel them.
Do you have any close gfs you can reach out to? My friends who I thought would tell me to leave were the most supportive group of women I know. I was cautious about who I told and kept it to a minimal, just my closest gfs who I rely on the most but it took me time to go to them as well. They were my saving grace in the early weeks when the truths kept trickling out. If they are true friends, you may be surprised by just how much non-judgemental support they can give, but you do have the responsibility of choosing who you confide in wisely. Local support groups or a counselor you can access? This site has been very helpful for people who can relate to what I'm going through, but counseling has been vital in working through my emotions.
Keep checking back and just allow yourself time to deal with this. You can't rush the process, no matter how remorseful and helpful he's being now.