Don't say sorry for being emotional, and it's definitely ok to continue posting here, I'm sure I speak for many people when I say that it's good for everyone to hear the reality about all aspects of married life, not just wedding planning.
I think you're right to slow things down a bit in terms of trying to get the practicalities sorted; there's absolutely no panic on doing that kind of thing just yet, it's only been a matter of days, so unless it's giving you some sort of healing, then don't bother with it just now. Changing the locks was a big step and fair play to you for doing that; you're dead right, I know so many women who have exes sauntering into their houses whenever they like, simply because it was the family home and their children live there, but it gives you no privacy or dignity at all to have someone else controlling when and where you come face-to-face. Good on you for taking that bit of control.
And I can totally and utterly understand why you're thinking about what to do if he comes back and tries to make things work; of course you're going to think that way, for ages now you were putting every bit of your heart and soul into trying to make this marriage work - you're still invested in it, regardless of what he has done, so it will either take time for that to fade away, or he will come back and ask you to give him another chance, but either way, you just have to focus on yourself and what is best for you; it's not about him. If you come to the conclusion that you would prefer to stay with him and he comes back asking for a chance, then that's totally fine; it's your decision and nobody else's, there are thousands of couples who give it another go after infidelity, sometimes it works, sometimes it doesn't. But don't be afraid to do what you feel is right for you, and if there are people around you trying to force you to maintain a certain attitude, then you need to explain to them that you need their support no matter what you decide, you don't need to have someone else's morals shoved down your throat.
This is about you and what you want in life. Obviously I'm hoping that you flourish without him, it sounds like the relationship has bee really one-sided for a long time now and that you're an extremely loyal and kind partner who was taken for granted in the extreme, so in theory, it would be nice to think that this relationship has run its course for you too, because you deserve to be in a much happier relationship, but ultimately it's up to what you want for yourself.
I can tell you, having had 2 long-term relationships before marrying my husband that sometimes moving on is the best thing you can do in terms of personal growth and confidence etc. My exes were good people, there was nothing bad about the relationships but they didn't fulfil me in the way my current one does; nobody's fault, just I wasn't getting a lot of the boxes ticked, despite feeling very loved up and happy, it did fade after a number of years and although it felt scary, I did leave and move on and experienced other things which made me feel so much more confident and self-assured; it was hard but it was the right thing. Now I'm with my husband and I feel like I can say anything to him, I am really upfront and have no qualms about saying "I need you to do this for me" whereas before I wouldn't have really known exactly what I wanted for myself, not to mind having the guts to ask for it. I always put my partners first, as if I wasn't important and it sounds like you do a bit of that too. Don't get me wrong, I think t's a default setting for most women; putting everyone first and ourselves last, and I still do it 50% of the time, but it's not all the time, and so ultimately myself and my husband are both fairly happy all the time because we know where we stand, we know we're both compromising and both getting stuff we want out of the relationship rather than things being one-sided.
Anyway, this isn't about me, sorry for waffling on - I'm just trying to say to you that while things might be about to absolutely explode for you, and you have no idea what the future holds, use this time to be selfish and to focus on yourself; now that you don't have to put all your energy into trying to figure out what the feck is wrong with your moody partner, you have loads of time to just sit and figure out how you're feeling.