In my past I had been in a relationship with my boyfriend for 7 months but were mates for 1 yr and half, broke up 3 yrs ago, since then I have seen two guys for about 2 months each, & till this day I can not stop thinking about my ex.Is it wise for me to get back in contact with them through email,as that is my only form of contact?

They are exes for a reason, why not go forward and not back.