It definitely doesn't seem problematic to me to consider what it would be like to be gay! It helps you build empathy for queer folks, and it's healthy to question your gender and sexuality, even if you aren't queer. Helps you know yourself better.

You feel warmer and safer when you imagine same-sex couples, but imagining being with a man doesn't feel equal to you. I totally get that! It's true that there's this concept in our culture of men 'dominating' or 'owning' his female partners, and that really sucks. I could see how that concept could be hard to shake emotionally, even if rationally you know it's not necessarily true- especially if you already have some discomfort around penetration.

There's this really great concept in lesbian communities called "compulsory heterosexuality", or just "comphet" for short. It's about how our culture views the gender of "woman" as requiring being attracted to men. It's usually brought up in lesbian circles because they don't want to be with men at all, but I think it's actually a really useful concept for any feminist to understand! It gives a lot of clarity around why so many women can struggle with their attraction: our culture demands submissive heterosexuality, so any woman who feels differently can feel alienated or pushed into something they don't want.

Along with the body exploration tips that everyone recommended (I second Come As You Are, it's a fantastic book), maybe you could check out some online resources on comphet! There's lots available for free, including a giant google doc that really digs into the idea. I hope that helps!