How easily can people lose your trust?

My ex lost my trust the day I found out she was pregnant in early 2017 but she already knew weeks before and told her best friends several weeks before she told me. That was the first clear signal I was being used as a sperm donor to get the baby she always wanted (she's 47 and our daughter is her first and only child) and source of money to support her lifestyle (via child support), and now I've successfully achieved court orders mandating time with my daughter for 28 percent care she hates me and will not be in any place in public with me when our daughter is present. I'm not even invited to my daughter's 5th birthday party next month with all her friends from daycare and their parents (ironic as I'll be on annual leave from my job then).