ok hun.....This is MLC probably for sure.....but put that aside for a moment.....becuase whatever you call it .....it is a long road..and hard....and I hate to break it to you....If I could place a bet on the fact about another person...I would say 99.9% chance there is one.......oh my gosh he has all the standard lines.......and he is going for a vasectomy consult.......BIG RED FLAG HELLLLOOOOOO but even if you take that out......everything he is saying SCREAMS ANOTHER PERSON.....it sounds like you are doing all the right things with DB....sometimes no matter what you do ....in MLC it wont matter becuase they have to walk the path...that takes them to the train wreck........you just have to decide what you want for you.....are you going to go through seeing if reconcilation will be possible...more than likely that will not occur until the other relationhip ends......2- 4 years....
I would probably confide in his family.....I would probably verify there is another person...if he is that good at hiding it that you really cant tell....than hire a pi...but if you look....chances are you can find something....cell phone history....assuming you have all his cell phones....usually they talk on the cell even if they try not too......
there is a site i think its marriagebuilders dot com and they go over the choices of blowing the affair wide open or not.....you read and decide......it sounds like he is really guilty about that and wants no one to know.....so if you can find out speak the truth in love....I would consider blowing it wide open once you get the facts.....
so sorry you are going through this...keep posting.....