IS IT RIGHT?

I went through a pretty difficult time coupla months back, trying to decipher wat i really wanted from the relationship i was in. It all seemed perfect, but I knew there was a problem, I loved him like my own skin, protected him and did my best to make it work, but we didn't share anything in common except our love for football. i knew he cheated twice (de times i was indeed aware) but I also forgave and kept loving, BUT was I right?, was I too good? was I too quiet? these are questions I keep asking me. I've heard folks say, "fight to keep love" but I aint no fighter! I'd rather love........ so i let go @ a point, cause no matter how deeply i loved this guy, we just weren't meant to be. its been 3months now, I'm relieved I let go even if I still get the nostalgia feeling of been with him. Couple of hours back my kid sister sent me a text saying she just broke up wit ha boyfriend of over 5yrs, and I'm wondering what went wrong? I asked her and she says she cant cope no more. My concern is this (has always been) is it okay to let go after all these years or does it make sense to hold on and try working things out instead of starting from scratch? how are we sure the next guy aint worse? how many more are you willing to let in, all in the name of searching for MR. RIGHT? Are we ready to let in some other stranger who acts all nice from point "A" and show his true colors at point "K"??!!?? If we cant work hard to make a realtionship work then how can we make our marriages work in future? Is it just right to let go of something you really cherish cause of problem worth solving?