Could someone advice how to handle a friendship with a new friend

Myself and my wife are Immigrants couple from Texas, originally from India. We are not that much outgoing type.

We met an American lady more than a year ago at our son's soccer classes. Her son was also attending there. We used to talk her. Later we moved our son to a different club near to our home. About 3 months ago we met her and son on a game. She came to us and we had a good talk. Later we (myself and wife) exchanged our numbers with her.

She started to message us and my wife occasionally reply. Everything casual. Later she started to call my wife and talk. Then only we came to know that she is a divorced single mother. Her elder kids with her ex and only this boy with her.

Now a days she call my wife daily and never crossed any thing on calls or messages. Last week she invited us to join her house for Valentines day dinner and told her other friends also would be there. We thought it was ok and agreed to.

But on 14 evening when we reached there we noticed that it was only us and no other friends.

She seems very happy we joined. We had a good dinner and casual discussion. But I feel some uncomfortable about her intentions. It was obvious that she had only invited us.

The boys have a good friendship. Sometimes she's suggesting plan some summer trip together.

I feel some uncomfortable feeling on her interactions.

I think might be my cultural background causing this feeling.

How should I proceed with this. Do I need to ask my wife to take break from this friendship or avoid daily calls and respond only occasionally.

I don't want to hurt anyone but don't want to get into some uneasy situations.

Any advice welcome.

TL;DR; I 42m married with 38f have some uncomfortable feeling on a friendship with a lady 44f (mother of my son's friend).