A theme featuring "life" partners in the form of two-word phrases each word in the two word phrase can go AFTERLIFE to make another known phrase. The first one I got was INSURANCEFORM, but my favorite life pairing was LIFE FORM.
Overall, a pretty smooth solve, although "Fraternal letters" at 38A had me trying a few Greek letters until the Downs revealed the answer to be BPO_. I thought I might FWOE thanks to 28D, where the end of the Latin phrase "Agere sequitur ___" was wanted, but I was pretty sure the final word of the phrase had to be ESSE and so I went with BPOE and got the congratulatory message. Horace tells me it stands for Benevolent and Protective Order of Elks.
Another interesting bit was the term "jackpotting" being attacks on ATMS.
I enjoyed the clueing overall:
"Names as a source" (CITES)
"Arrived dressed up like" (CAMEAS)
"Bounce back" (RALLY)
"Make changes to the board" (ERASE)
I don't know the app, but I like the word BEJEWELED. I also liked ENTITY and PIED.
Fun to see "Ire" on the clue side for once, with the long ILLTEMPERED as the answer. ENLARGEMENT is another nice big answer. My favorite non-theme related clue was "Fitness center?" (CORE) - ha!
I haven't heard the term MAINMAN in a LIFE TIME.