This is the kind of thing I could be fine with in a primarily-LDR relationship (given all the work travel), but is he expecting monogamy and to be his new partner’s primary partner and highest priority, whereas she’s lower on his list?

(My daughter’s father, from whom I’ve been divorced for 27 years, is our housemate when he’s in town — for similar reasons, his job has him on the road for 10-11 months a year — but thankfully people do understand that we’re not together!)