Thank you for the additional information. And yes, I am a licensed mental health counselor and psychotherapist and this is a legitimate service. This problem is bigger than just one incident of infidelity as your husband has done this before, and now you suspect with more than one woman. I can understand how heart wrenching this is for you and affecting you on many levels.
The first thing that needs to happen for you to begin the process of rebuilding trust after infidelity, is that the offending partner (your husband) does need to answer any and all questions you have about these indiscretions. Of course he is embarrassed and doesn't want to go into discussion, but you deserve to know whatever you would like to know and have long, honest discussions about this!
You are his wife of 28 years and raised children and you certainly deserve better treatment and respect than this.
When you say, that you were despondent over your mother's death, you needed support and comfort at that time, and yet this is when he began an affair. There is alot to work through here and you have no reason to trust him, as he has shown himself to be untrustworthy.
You need to now think of yourself and taking care of you. I would really recommend that you seek out counseling in your area with someone who helps people through infidelity. Tell him that you are doing this and that he needs to attend and be part of the process of healing. If he says no, then tell him (if you feel this way) that you will then go on your own and don't expect the marriage to heal on it's own, without him.
That he is 100% accountable for his own destructive choices, and if he isn't willing to therefore do the necessary actions to rebuild, that you don't know how the marriage will endure. In short, you set a boundary and you follow through. AND you go alone to the therapist if he won't go as you will need ongoing support and counseling regardless of what happens in the marriage.
If you would like to give me your zip code I can find some therapists for you in your area... couples do survive infidelity and restore trust, with mutual willingness and the work from both people it takes to repair the damage. If you do allow him to just sweep this under the rug, then you won't trust him of course and he may just continue the behavior whenever he is in need. Please click ACCEPT button for this answer and feel free to continue the discussion with me even after clicking accept. Thank you,