Has his daughter's mother returned?

I am Immy, 23, and in love with a 42-year-old man, who has a daughter from his past relationship.

I love this guy, he has been there for me financially and he loves my one-year-old daughter. We have been happy in a relationship for one year as our children have bonded through playing together.

However, since this month started, he does not allow me to go at his home without calling him first. He  prefers to come at my place, which was not the case before.

The last time I was at his place I noticed lady's shoes under the bed. When I asked him about it ,he told me the shoes are for his sister. Could the mother of his daughter be back? What should I do, I feel we can work this out.