You said
I've also established some more strict boundaries with her. She can no longer spend any time with another guy without me there. I trusted her before to be able to do this, but she's shown that she can't.
I will tell you something. I agree with Mel on this, but I think you have something very very wrong.

The boundaries that need to be in place with a PLAN to enforce them are HER boundaries not boundaries you set for her. Until she can come to you and tell you about her boundaries going forward and how she will protect them, you are simply becoming her watchdog, relieving her of the responsibility of facing her own failures.

She has to have a "come to Jesus" meeting with herself and face what she has done, how she has allowed her boundaries to be crossed or why she did not have any boundaries. Then she MUST come up with a plan to protect her boundaries and your marriage. Until she does this,you won't recover. This information must be conveyed to you, and then the two of you assess her plan and tweek it so that it is a win-win.

You see if a simple conversation leads to her falling in bed with some guy, you are not the problem here. People don't drop their pants just because they haven't "really communicated" for awhile. There was something else going on.

Please think about this.

God Bless,