Thanks for the additional information.
It's no wonder you are troubled by fears of her cheating. You have many rational foundations for this fear. Just because there are many risk factors here does not mean she is, has or will cheat on you.
First let's look at the risk factors:
1. family history of infidelity.
2. long periods of forced separation.
3. History of infidelity in the marriage relationship.
While all of these are significant risk factors they do not individually or collectively predict further marital infidelity.
Let me go through the list and demonstrate:
1. Family history: Many people seriously vow not to behave as their parent(s) did in any number of areas and are successful in keeping their vow. I know one person very well who has been married for 29 years, 5 months and 13 days who never cheated on his wife though his family history was riddled with infidelity and divorce. If there is one that goes against the tide then there can be a second, and more, maybe your wife is one of them!
2. Long periods of forced separation: When living in a military culture marital infidelity is a prevalent issue. Just because it is prevalent does not mean it is inevitable. As you know from your own experience you can choose your behavior and you can re-choose your behavior regardless of your circumstances.
3. History of marital infidelity in your relationship: You may be projecting your own guilt on to her. Have you forgiven yourself? Has she forgiven you? If you are a believer, has God forgiven you ? Are you past it? Do you still struggle with temptation? There may be a part of you that actually wishes she would be unfaithful because you feel you deserve to be punished or you want the score to be evened to assuage your unresolved guilt. To what ever degree you have not come to complete peace on these issues you may tend to unconsciously project them onto your marriage, (heavy but true).
If you believe there are spiritual forces at work in our lives the following may apply. If not then skip over this paragraph. Good is in favor of stable secure marriages built on trust and fidelity where parents and children can grow in an environment of security. Evil is opposed to such situations and will do all possible to destroy them, including instilling and encouraging doubt between marriage partners. And so the battle is raging and it is more than physical, mental, emotional, situational it is also spiritual.
If this applies you may need some spiritual reinforcement as well.
Lastly: If you are suffering with clinical anxiety
and/or depression the mind will often look for a tangible cause for the symptoms the body is experiencing. It is as if the mind says, I know there is a reason I am feeling fearful I will find it and attack it. The mind chooses the threat of marital infidelity and begins to obsess on it and thus feels a sense of control even though it is misdirected. If you think you may be struggling with a chemically or physically caused anxiety or depression, get a good physical exam and consider consulting a medical specialist i.e. a good psychiatrist. There is no shame in this and it may help.
Thank you for your military service to our country.
Best of success and happiness to you and yours.