How to "test the waters" without being 100% sure

Hey everyone! I have recently come to the conclusion that I might be gay or bi (leaning towards women) and am just wondering how I can know for sure, or if I should even try. I know there are a few posts like this, but I went through a few pages of posts and couldn't find a backstory that I could totally identify with. A little about myself:

I'm in my mid-twenties, I've always dated boys and just got out of my third long term relationship. This was long distance and ended due to us growing more as friends than as romantic partners. He was a great guy who I cared for a lot and would never do anything to make me uncomfortable, but by the end, I hated sex and would dread seeing him in person out of the fear that things would get physical. Interestingly, the last time we saw each other, we were broken up and I felt so relieved of any dating pressure that we actually had really intimate and passionate breakup sex. He's also the only person that I mentioned my possible gay/bi-ness to, and he was very supportive and encouraging of me taking the time to figure myself out.

Throughout the relationship, I would occasionally think about his girl friends (I even had a little crush on his ex at one point, who was bisexual) but didn't ever think anything of it. I've never experimented with girls and have always been drawn to having guy friends (minus a few very close girl friends who are like sisters to me - absolutely no romantic/sexual attraction). I remember checking out/comparing my body to other girls when I was younger and worrying that they would think I was a lesbian, but besides that and the occasional lesbian porn or sex dream I don't really remember having a distinct "phase" when I was totally into girls when I was younger. I do have a lesbian cousin who I look up to and deeply admire, and every time she brings home a girlfriend, I look at the connection they have and think about how much I want to have that with someone.

I've hung out with boys since I broke up with my ex, but there were no sparks and they all ended horribly - one guy tried to have sex with me in a theater on our first date, one guy spent one day with me as platonic friends before texting me all about his fetish for bondage and leather, etc. My sister set me up with an online dating account, and after not finding any captivating guys in my area, I spent a lot of time looking at the bi and lesbian girls in my city and other cities. I'd always been curious about dating girls and would have no objections to dating someone of a different gender/orientation if I met the right person. However, I am completely uneducated about lesbian sex and have no idea if I would enjoy it. I don't particularly LOVE hetero sex, but I at least know how it works, haha! I also am very distrusting of men at the moment and am wondering if I've just convinced myself that I should "try" girls because my last few attempts with men failed. The idea of having sex with a woman scares me because I have no idea what to do, and I don't know if I could dictate what I wanted. I enjoy men as companions (as in, doing activities together as friends), but I have never actually fallen hard in love with any of the guys I've dated.

I want to figure out whether I am actually attracted to women or if I am just at my wit's end with men, but I don't know if I can do that without actually getting physical with a women - and I'm not really in to random hookups - and wouldn't it be unfair to someone if I started a relationship with them just to see if I am attracted to their gender? I feel like I would be using her, and I'm not out to hurt anybody. How should I go about figuring these feelings out? Does it sound like I'm just in a "men suck" phase?