Ok, but the point is.... he didn't feel the need to do this. He never suspected. I can understand if you are already suspicious and need proof or verification.
But I can understands how he feels. I trust my partner to be completely honest with me. I believe 110% he is. I would never suspect him of doing otherwise. Not with us talking of long term future plans like adopting a child or something. And to just innocently discover this side of him? It would be like stepping out and getting blind sided by a cement truck. Not the fact he slept around, but he went through such openly deceptive means of lying about it and where he was going, and then actually bragging to other people that come into our homes about what he was doing, making me look like a naive fool. That is the part. It would be different if he were already suspecting something and looking to confirm his fears.
But to sit down and BLAMMM!! your world blows up in your face?