Is it normal to feel angry, upset, guilty, etc all in the space of a few minutes
Yes, but it will pass, just push through it. Stick on some really "up beat" music on loud, sing along, and clear him out. Good mantra for this one is "Think, not feel, Think, not feel, Think, not feel"
Don't take it to the other woman, don't aid him in making her his next mark, not to mention it will send him the wrong message, he will interpret it to mean that this is jealously rather than the end of the line. Take it to his work. No emotional messages, just clear instructions to stay away with the threat of the authorities to underline how serious you are.
Get a new sim card today, call everybody you want to have your new number, use it as cleansing process to dump anybody who you don't look forward to calling you, put one more blockage between you and him by being that bit harder to contact without too much effort. The energy involved in changing contracts is not worth it and extends the tie to him. If it is in his name then the bills are in his name, so it will be his problem to sort out.
He is under the misguided impression that he can 'form a new relationship' and use article 8 of the Immigration act to stay in the UK.
Well let immigration deal with that, just tell them everything you know, in writing, and let them do their job.
You are not the first love, my first husband was Thai and after five years together we went to live there for the last half of our marriage. I had so many friends, colleagues and acquaintances that ended up as marks. Young, not so young, pretty , not so pretty, well off, not so well off.........all it takes is a time of vulnerability and somebody with honed skills. Don't beat yourself up, nobody gets through life without some regrets and "what the fuck was I thinking"s.
On and up, yesterday is done, time for something new.
(big fat hug)
and get that music on (=
You are going to be just fine, these are the last few pushes to birth a better next phase of your life.