This is going to weird and irrational, but hear me out.

I have this irrational fear of me marrying some woman and her up coming out as a lesbian years later (I'm a male). If you've ever watched Friends the same thing happened to Ross with his ex-wife Carol. I worry because then that would mean I wasted years of my life with someone biologically incapable of loving me. After the divorce I would be too old to find love again. In order to "cope" I used to try to imagine that I could "spot out" if a girl was a lesbian and then wouldn't be attracted to her.

Well when I hit on this girl in college she told me she was a lesbian and had a girlfriend. I felt really awful about it. It felt like I had one foot in the pond. I feared for months about falling for a lesbian and I kinda failed. I never dated her of course but if she would have been insecure about her sexuality and tried to date me then I my fear would have happened for real. I felt like I personally failed because I failed with the one thing I obsessed over for months. Now I realize that I will never be able to "tell" if a girl is lesbian and that I could end up accidentally marrying one.

I know this fear is irrational and that it's very rare to happen, but not impossible. How do I stop being so paranoid about this? I feel like this fear has subconsciously deterred me from dating. I haven't asked out another girl since.