Recs for M/M series focusing on the same couple throughout? Hello, all!

I'm looking for any suggestions for series, ongoing or complete, following the same couple for the whole run. I prefer historical, fantasy, or steampunk-type settings but I'm not opposed to a solid contemporary. I'm also a sucker for relationship drama, angst, 'broken' characters, anything that will give me a good gut-punch of emotion here and there. I like something steamy, but I don't want those scenes to be the whole focus of the story.

I've got major book hangover right now from going through the Whyborne &amp; Griffin series by Jordan L. Hawk in about a week. I want something in a similar vein, following the same characters and preferably with an overarching plot that covers multiple, if not all, entries. Any ideas? Thanks in advance!