It could be issues, or it could be that none of those people were quite right for you, and you didn't want to waste time and energy on something that was never going to go anywhere.
Until I met my husband, I eventually lost interest in everyone I dated after 6-8 months. My first "real boyfriend" and I dated for 15 months, the last 5 of which were mostly fighting.
As for whether you're a lesbian, that's just something you have to figure out in your own time. My hunch is that if you like sex with men, then you're probably not a lesbian.
Some people are afraid of commitment, throwing away perfectly good relationships when they get too intense. Other people just have a good sense of "this is not my life partner" and walk away when the cons outweigh the pros. My husband was the latter. He had never had a relationship last more than 6 months until me because he didn't feel the connection to them.
Gralson: my husband (works out of town).
Auto: my girlfriend (lives with her husband Zoffee).
The most dangerous phrase in the English language is "we've always done it this way."