(Because the only thing I might like better than Matt/Frank is Matt/Steve.)
Matt and Steve have been acquaintances/friends/sparring partners for a while. Steve is starting to develop a serious crush on the lovely lawyer, so he decides to ask him on a date. Matt explains that he's already seeing someone, but won't say who.
Steve eventually figures out that Matt has been sleeping with the Punisher, whom he already has more than enough reasons to despise. Cue jealous!Steve giving Frank the shovel talk, and just generally being really antagonistic towards him (while Matt dies of embarrassment in the background).
Bonus: + Steve initially thinks that Frank and Matt's thing is purely physical, but he eventually realizes that there's a lot of tenderness there, too. +++ If the Punisher and Captain America have to put aside their differences to rescue Matt from bad guys. Double Bonus if Matt's already halfway to rescuing himself when they arrive. Triple Bonus if Matt let himself get caught specifically so that Steve and Frank would have to get their acts together. +++++ If Matt suggests that they resolve the problem by forming a threesome.
Steve Rogers/Matt/Frank Castle Love Triangle
Matt and Steve have been acquaintances/friends/sparring partners for a while. Steve is starting to develop a serious crush on the lovely lawyer, so he decides to ask him on a date. Matt explains that he's already seeing someone, but won't say who.
Steve eventually figures out that Matt has been sleeping with the Punisher, whom he already has more than enough reasons to despise. Cue jealous!Steve giving Frank the shovel talk, and just generally being really antagonistic towards him (while Matt dies of embarrassment in the background).
Bonus:
+ Steve initially thinks that Frank and Matt's thing is purely physical, but he eventually realizes that there's a lot of tenderness there, too.
+++ If the Punisher and Captain America have to put aside their differences to rescue Matt from bad guys. Double Bonus if Matt's already halfway to rescuing himself when they arrive. Triple Bonus if Matt let himself get caught specifically so that Steve and Frank would have to get their acts together.
+++++ If Matt suggests that they resolve the problem by forming a threesome.