Should I Get a Paternity Test?

I’m not too sure if this will get any responses, this is my first post on reddit.

My girlfriend (30F) and I (22M) just welcomed a beautiful baby girl into the world in February. When she initially got pregnant, we were not using protection, but I did not leave it inside. With that being said I am already well aware that the possibility of pregnancy this way is still very high.

I would like to first state that I am extremely grateful and excited to be part of this journey, and in no way, shape, or form am I trying to find an “out” or find a reason to leave (I already signed the birth certificate).

My issue lies here: I trust my partner now, but I also saw a different side to her before we got together.

She was known to be very flirtatious and accused to be promiscuous, which we have already talked about, and we agreed that the past is the past. However, she got pregnant about a month and a half of us being in an official relationship. A week before she told me of her pregnancy, she took a girl’s trip to Europe, and shortly before and also a bit during our phase of getting to know each other, she was seeing another guy. (He was asian and this will be important in a bit).

My own insecure voice in my head kept telling me “what if she hooked up with someone in Germany” or “what if she hooked up with the Asian guy one more time before we officially got together”. With this in mind, I’ve tried asking her it we could get a test done, to which she replied she would immediately leave me if I was being serious. No matter what I said or tried to explain, the ultimatum was simple: test and be single, or blindly trust and be in a relationship.

After my daughter’s birth (who is now a month old) I don’t really see any similarities to my likeness. Ive even been told she looks a bit Asian (hence the importance of that being mentioned above). I seriously cannot get this out of my head, but I can’t talk to her about it for fear of ruining our relationship. My reasons aren’t anything major, and are built on insecurity and past experiences, but I cannot get these thoughts out of my head. It really alarmed me about how adamantly she refused to even entertain the idea of getting a test done.

Do I get the test behind her back? Am I just being insecure? Are my feelings even valid in all this? She definitely has not done anything during our relationship that would make me mistrust her, but again, I’ve seen a very different side of this woman and it makes me question things sometimes. Any advice would be appreciated.