Do the things you want to do.
My husband and I are both business owners and are successful as well - we enjoy the finer things in life, and have the means to do so. We have been in situations where we pay for everything, and situations where we split. Generally I go with what feels right for the situation, and whom we are involved with.
When we were in a quad, we almost always split everything. They'd pay for their half of dinner, a getaway, a fun night out on the town, etc. Sometimes two of us would host the others, and then we'd pay for all of the food/drinks, but they'd often show up with dessert and a little present for having us over (they never hosted us, as they had rules about "play" happening in their house). I bought all of the safe sex gear that I wanted him to use (good quality condoms, lubes, etc), because that was a priority for me, but he sacrificed some days at work when he got a vasectomy so that he couldn't impregnate me.
When dating poly/single women on their own, it often depends on what we want to do. If we want to go to a pricier restaurant, but our girlfriend is a student, then we pay. We can always choose dates that she can afford if she wants to treat us to something - a picnic, beers, or ice cream. When we want to go to the symphony and stay at a nice hotel, we pay, but she's welcome to treat us to a bottle of wine, or pay for parking, etc. I might send her flowers, or deposit money in her bank account for lingerie shopping, etc, whereas she would make us a mixed CD, or cook dinner for us, or give us nice back rubs for a less expensive present.
Our current girlfriend is great with money and is financially stable, but we still have treated her to the first couple of dates, as we are dating/pursuing her and want to honour her. She wanted to pay for dinner the other night, but I could only bear to concede to have her pay for her half, because if I had known she was going to want to pay I would have been more conscientious about what I was ordering.
So all in all I think it comes down to: Who can afford what? Who wants to do what? I don't think it needs to be all that balanced with dating, but living together needs more of a negotiation/place for finding a balance that worked well for everyone, and didn't leave anyone feeling taken for granted. Perhaps if you're with someone who can't afford much, they could take over a larger portion of household responsibilities (grocery shopping, keeping house, etc) so that they're making a contribution that is different than financial. However, if you're in a position to support a lover who wants to live with you while they, say, go to school, I say do it! You'll be having a fabulous experience and getting to share your love with someone else, and if it's easy for you to provide financial support, then I say why not?!
Our last shared girlfriend that we lived with paid nominal rent (like $300 a month or something like that) to contribute to household expenses, and paid for 1/3 of the grocery bill. We took turns buying stuff like wine, or treats, but I was fine with that as she was a working professional. We didn't need a lot of money from her, so I didn't ask for much in terms of contributing. She did take over a bunch of the household chores though, which was really sweet of her, and appreciated as we're all so busy in our lives. Gave us more time to relax together, spend time with friends and family, etc.