Love meaning Eros, in this case.
I'm thinking there must be some marriage/dating relationships where couples are more focused on Love over Friendship; and others where they are more focused on Friendship over Love; and maybe a couple (particularly Duals) where Love and Friendship more equally go hand-in-hand.
Obviously, a long-term relationship will require a good balance of both Love and Friendship to survive. Love without Friendship will result in little more than partners "using" each other for sex; and Friendship without Love, well, they'd really just be better off as friends then.
If a particular intertype relation naturally tends more towards Love and less towards Friendship, lovers who want to stay together will have to learn to make adjustments in order to become better friends. If a particular relation naturally tends more towards Friendship than Love, but the partners still want to make a life together, they will have to learn to kindle their romance even though it may not come as easily (personally, I find my own relationship with my ILI husband falling into the latter category).
Totally basing most of these on loose intuition, nothing really rational to back most of it up, so do feel free to disagree and discuss...
Pairs more likely to be Lovers first: Semi-Dual, Benefit, Super-Ego, Conflict, Contrary
Pairs more likely to be Friends first: Identity, Mirage, Mirror, Business, Supervision, Kindred, Quasi-Identity
Pairs most likely to have a good natural balance: Dual, Activity