It is very likely that your wife is having an affair. It is also likely physical since she has cut you off sexually. This usually happens when the infidel doesn't want to be "unfaithful" to the new partner.
The first rule for cheating is that all cheaters lie. The sooner you learn that rule, the better off you will be. What that means in real terms for you is that anything she says or does, especially involving activities away from you, is highly suspect.
You will need to start doing some quick work on yourself. If you are being grabby, needy or controlling, then you need to stop it immediately and change your behavior.
Next, you have some emergency reading to do. Get a copy of Michele's book. Get a copy of "Surviving An Affair" by Willard Harley, and get a copy of "Not Just Friends" by Shirley Glass. Read all three books. All offer similar perspectives and approaches to the problem. All provide unique remedies. You will need to devise your own strategy from the three. Don't let her know you are reading the books with the exception of "Not Just Friends". Leave it out in plain sight. For now, this is the only hint you will give her that you know what its going on.
Don't waste your time asking her about an affair, she will lie. Do some detective work and get your own proof, then confront her.
Whatever you do, do not facilitate her affair. That means you don't pay for her to have it, you don't help her with apartments, stop funding her activities away from home. Get your finances separated immediately (especially any savings). Get legal advice about protecting your rights.
Get ready to fight to save your relationship. She just threw the first punch.
Let us know when you have taken the first steps.
All the best, -NOPkins-
I will ferret out an affair at any opportunity.
-An affair is the embodiment of entitlement, fueled by resentment and lack of respect. -An infidel will remain unreachable so long as their sense of entitlement exceeds their ability to reason.