This is the same situation in my relationship: my partner travels between two homes, about 1.5 hours apart. Not sure if you're looking for advice, but I'll share what's been working for us, and what the challenges have been...
- GAS! - My partner goes through a TON of gas getting to work and back when he's at home with me (1.5-hour commute versus a .5-hour commute from his other home). His car needs premium, to boot. You're not at the "commuting" stage, but if it gets there, be aware that there'll be an added expense.
- Distance from my partner's "life" - It'd be a challenge regardless, but there are times when one of his friends is playing at a club on a Thursday night, and I can't go because I either need to work the next morning (and can't add the extra 1.5 hours onto the end of the night), or don't want to stay with him and his OSO because I'd be uncomfortable doing so. Other things, like casually getting together with his sister for coffee tend to be something he can do with his OSO, but we haven't been able to do together, and it can be a bummer.
- Kid schedules - my partner and I are both divorced, and things like having to pick one of the kids up at 7am, or having to wait for a gymnastics event at 4pm tend to impact the travel back and forth as well, but again, that'd be a challenge regardless
- Projects - I have a 1930's house, with no end of "projects" in sight... I want to be veerrrrry careful about starting a project if my partner's not going to be around to help finish if I need his help. Not a big deal anymore, but I felt abandoned once before during a big project (unusable shower/tub), and that stunk.
The big plus here, though, is that he and I feel like we're building a life, a future, and a home, and he gets that (differently) with his OSO. I do not want a group living arrangement (I don't ever want another roommate, ever. Period. Blech.
), so this works for us. He's not around 24/7, which also helps me indulge my independence a bit, and lets my kids feel like he's not usurping their time with me. Not that I wouldn't enjoy more of his time, but we're doing well with what we have.
Hope all goes well for you and yours - it sounds like it is!