Balaclava,
You are experiencing much pain and anguish. Although we all here at SI are thousands of miles away, we are only a screen length's away from you to comfort you.
I'd like to summarize what we know so far. You have found out about your WH's infidelity after stumbling upon a condom in his pocket. Upon looking at his iPad you found out that he has had multiple affairs and has been visiting prostitutes. It appears that your husband is slowly trickle-truthing you. You have two girls and are aged 44 living abroad and probably separated from your family. We know your WH is technically savvy.
I'm sorry to be blunt but this slow trickle of the truth will continue until your WH is faced with the stark possibility of him being thrown out. He will continue to lie, cheat, and continue his ways until you stand up for yourself and put a stop to it. If you want to save your marriage, there is still a small window of opportunity. Here is what I would do:
1) Gather any evidence you have now. Emails, pics, photos, texts. Create a separate email account that only you know the password for and send copies to the new address. Avoid logging into this account from computers that he has access to (he probably already installed loggers on them to spy on you). Print out copies of any evidence and store them safely out of the house. If you have the money, hire a PI.
2) Go see a lawyer and find out your rights. I know you are living abroad, so you may also consider consulting with a lawyer from your home country as well. Get D papers written up. These papers are mainly for shock value, as it often snaps waywards out of their fog.
3) Expose: you need to expose your husband's filandering so that he can be publicly shamed. Do you know the names of the OW he had affairs with? If so find out who their husbands are. Contact them and show them the evidence you have. Don't warn your husband ahead of time that you are going to do this, as it will give him time to do damage control. Just EXPOSE. It will be the single biggest weapon you have to shock him back to reality. Expose to people who are close to you both (friends, family, religious leaders). Keep the exposure simple: explain that you want their help in saving the marriage and that your H has gone astray and that you need their love and support during this difficult time. The purpose of exposure is not punitive, but for the wayward to see how much their actions harm everyone else around them.
4) Once you have exposed, confront your H. In a way you have already confronted him, but not strongly enough. Show him the D papers and tell him that you mean business. Give him your list of demands else the papers will be filed and he will need to leave the house.
As far as list of demands, they are up to you, but here are some suggestions: 1) STD check full panel 2) Polygraph test 3) Access to all of his email accounts, phones, bank records, etc 4) No further contact with any of his previous affair partners and he writes formal NC letters to each of these OW 5) Definitely no more visiting prostitutes or brothels 6) No more guys nights out 7) No events with alcohol unless you are there 8) Activate the GPS feature on his phone so you can track him whenever you want 9) He needs to give you access to his calendar and update you on his whereabouts at all times 10) He needs to write out a timeline of events: each affair, when how long who, etc 11) Weekly sessions where you get to ask as many questions about the Affairs as you want, as often as needed 12) Individual and couples counseling
This is just a start. Keep posting and let us know what is happening, and we can help more.
...........................Kali