The business partnerships between small to medium sized software enterprises (SMSEs) and large IT vendors are prevalent today. In this paper, we empirically identified the factors that improve SMSEs' partnership performance and motivate them to retain their partnership based on interviews with and a survey of C level executives of SMSEs. We found that SMSEs' partnership performance and intention to retain the partnership are influenced by normative, technological, and managerial factors. Based on these results, we provided a set of managerial guidelines that can be useful for executives and entrepreneurs in SMSEs.