I (f18) am in a relationship with a woman (f18) but I yet still secretly long for a male partner, what should I do?

I (f18) am in a now 1 and half year relationship with my girlfriend (f18). Im really happy with her, I do love her a lot and she makes me a better person. We do have some struggles in the relationship due to her mental health but the relationship by itself is a solid one and Im super satisfied, as it comes really naturally.

Now, Im bisexual but previously to her I never really wanted to date women. Sure I found them attractive and emotionally interesting but due to cultural reasons I wasnt really down for this hassle as my parents are homophobic, and Im not publically out and also still dont want to be. I live in a progressive european country but come from a rather conservative one. I also dont like having people in my business, so thats why I wasnt really interested in dating women / coming out.

Well she came along and we hit it off and got together. Only my closest friends know and they say that we are a really sweet couple.

These past 1.5 years I have noticed myself, that I do seek out male attention, that I kind of get crushes on men and also catch myself trying to flirt with them. I seriously am satisfied with my girlfriend but I dont know why I still want a guy??

What got me to write this was my experience this summer: I was back in my home country and met a guy. I was really interested in him and sought out his attention. I started fantasizing about him and wanted more with him. The silly thing is that I really liked his masculine features, like his broad shoulders or his big arms. I know its so stupid but I really started crushing on him.

Now realistically, I would never seriously try anything with someone else than my girlfriend, also I would never start something with someone over such a short period AND so far away from me.

But the unsettling thing is that I have these feelings, and cant do anything about them. I dont know what to do, as I notice in myself that Im not fully satisfied with just being with a girl. So Im wondering, what I should do. Telling her will hurt her and make her think that shes not enough for me but on the other side Im really uncomfortable with feeling this way as I do feel kind of ashamed and guilty and just dont have any solution.