How do I send this "thank you"....?

I am deeply sadden by this relationship and I need to send a thank you card for a card this person sent us with a giftcard in it.

This person is my old boss, we had a good relationship, I thought. I was her office manager and after her husband passed away and she closed the business, I still did some bookkeeping and property management for her part time.

After a couple years, I had gotten divorced and remarried to a man I met while working for the company she owned. I eventually quit working for her part time because my husband and I were starting a family and well, my ex-husband did her maintenance. When I quit I told her I felt bad, that I had a loyalty to her. She said don't, that our relationship isn't ending it is just changing.

But that was the last time we spoke, and that was a year and half ago. I have reached out to her a couple times to get nothing in return. But she has hired my husband several times for side jobs since then.

Randomly about 2 months, we receieved a "welcome baby" card with a gift card in it. I was shocked because it was from her. But I was also sad. I needed to send her a thank you, obviously but I sent her a text first explaining that once I got updated pictures back I would be sending her a formal thank you. Noresponse.

Now the holidays are over. I have the picture and the thank you ready to write but I don't know what to say. I feel like I need to share how I feel but I am the only one who cares.

I just need help processing this. I am so hurt, I stay awake at night thinking about it.