I am going to give you my opinion on your sitch. First off I am not a big proponent of using MLC as an excuse. Everyone on this board could argue to a certain extent that their spouse is going through MLC. We are and our spouses our all fuching adults and are responsible for our actions. "MLCers" don't commit murder right? Why? Because their actions are controllable and they are aware of the consequences when they commit murder.
IMO based on three years of research your main problem is that you are acting like the woman in the relationship and that is a big turn off to your W. For C sakes, she tried seducing you and you rejected her because of your feelings???? You are always talking about your feelings which is feminine energy. You are not acting like the leader of the house which is masculine energy. You are letting her manipulate you mainly because you are afraid to lose her.
Until you start acting like a man that loves and values himself enough to put up with this BS behavior you will see zero change in your sitch. I am 99% sure she is in an A and no she can't go on a trip with another man while she is married to you.
Can you control her? No! But you get to decide what you will tolerate. As Sandi says "get your fuching b@lls out of your Ws purse" and decide what kind of boundaries you are going to set up to protect yourself.