Should I Do The Paternity Test ?

Currently pregnant ( 20 weeks ) I heard there’s a Non-Invasive procedure that can be done to find out who the father to the unborn baby is. The only con is that it’s expensive ($1,600). The only reason that I’m considering to pay for it , it’s because I’ve been stressing over an incident that had happened (back to October , when I conceived) Basically I was messing around with this guy , we never had sex but he fingered me (before he did that he was jerking off possibly came but I didn’t noticed if he actually did) If he did had cum on his fingers are the possibilities high that he got me pregnant?

Also this happened on the Oct 27 . I know it might sound stupid but it’s always in the back of my mind. I was also with my now bf ( whos most likely to be the father of my baby ) we had unprotected sex multiple times that month ..

To be exact it was Oct 12 , Oct 20 , Oct 28. I asked my doctor when I conceived and he said around the 28-29 of Oct (closer when my bf and I had sex ). Am I tripping or should I get the test to be sure ?