I went through the same struggles TO back in the day trying to figure out the fascination girls had of wanting and needing a "bad guy" and got tired over over thinking it. To a degree I guess I could be been considered a "bad guy" because I wasn't a saint myself and dated a couple girls at the same time. But while doing so I also realized while attempting to be that "bad guy" that it came with alot more headaches and excess baggage.
Being the nice guy definitely has its advantages. So, I got back on track, wasn't looking for a relationship and next thing I knew I was standing at the altar saying my vows to my beautiful wife of almost 5 years.