Hello, I'm Alicia. Thanks for your question, I'm happy to help you today.
I can understand that you're feeling scared by this entire situation, especially since you say that he is the only person you have there. It can be incredibly isolating to have to deal with a situation like this on your own. But as you said, that alone is not enough of a reason to take him back. The fact is, he broke your trust, and it's not just a matter of a one-time affair that happened over the course of a few weeks or months (of course, that would be bad enough), but it's the fact that he's been having these online relationships for three years. It's the length of time that concerns me the most, to be completely honest with you, because that means he hasn't been truthful with you for three years. That's a very, very long time to be left in the dark about something like this.
That being said, it's not impossible for you to work things out with him, if you want to. You have been married for 28 years, which is nothing to sneeze at. Although you're the only one who can truly answer your question, I think you have to take a look deep inside and examine your true feelings for him. The idea of being alone is scary for anyone, but that's not a good enough reason to give him another chance. You can make it on your own if you need to, but that's besides the point.
In your husband's favor, he did
finally tell you about the affairs, but only after the other woman returned back to her husband. So would he have come clean if she didn't do so? What worries me is that he's only telling you the truth because he feels like his other "option" backed out, and if that's the case, then I'd have to do some long, hard thinking about how I want to proceed. If your gut feeling is that he's being genuine in asking for your forgiveness and that he truly loves you and cares about you, then it's worth considering giving him another chance. But if your gut is telling you the opposite, then you might have to give yourself some more time to think things over.
Unfortunately, affairs do happen. And relationships end because of them. But relationships can also survive them, especially if both parties are willing to be totally honest with each other and put in the work necessary to rebuild trust and commitment. But you both have to be on the same page. It might mean you need to sit down with him when you're ready and have a long, honest talk - and you might need to do this several times. I also wouldn't give up on the idea of counseling - you said separate counseling wasn't helpful, but you might want to think about giving couples counseling a try, if you feel like you do want to try to work things out.
I hope that helps, and I wish you luck. Please let me know if you have any further questions.