You might need to be careful. Check with your L about this, just to be safe.
I was in the opposite situation -- I moved out of the family home for the sake of my kids, and xW had at one point threatened to change the locks on me. She couldn't do that legally, not in our case.
In such a situation both parties are under some obligations, depending on the separation agreement or divorce terms. In our case, we were still M'ed at the time and I was the primary name on the mortgage. I was making all the mortgage payments and was due a key, which I retained. However, I was also very careful to make sure that I let her know before I would ever visit the premises -- and sought her approval first. You have to be extra careful in these circumstances, on either side.
The best arrangement we had is that I would visit the house under pre-arranged approval. Usually, xW would arrange to be elsewhere at those times because she was most interested in not seeing me more than really worrying about me invading her living quarters.
Again, your mileage may vary, but I suggest checking with your L.
