Jiraiya indeed. They had a nice moment when he told Tsunade that he's off for Hidden rain village to spy and promised to come back while Tsunade wanted him to stay and turn emotionally So they would imo come along good but as said he's dead now so...T_T
Hmm.. for some reason I don't quite see her as the monogamous type. lol. I think she and Jiraiya have more in common than she likes to admit, only, she can probably get it whenever she needs it, without having to pay for it