What to do with dog aggression?

Sorry this is a little long, but I figured I'd tell the whole story then ask my questions below..

About 8 months ago I adopted Kepler, my first dog, a 5-6 year old male Chesapeake Bay Retriever. He's been a great dog but he loves socializing with other dogs and keeps trying to play with the cat (who doesn't want to play) so I decided to get a second dog. 2 weeks ago I adopted Curie, a ~2 year old female Australian Cattle Dog mix. They met at the shelter in a largish pen outside and got along well. Kepler did try to climb onto her back but she gave him a good correction and he promptly sat down, then got and followed her but didn't try again. Curie came to me underweight but she's already put on a few pounds and according to the vet has another 5 to gain. She also has had very little training and is still working on sit, stay, and come, which she's learning quickly. Both are spayed/neutered.

Curie came home Tuesday, and the dogs seemed to get along well. I watched them in play in the backyard and they did very well, lots of running at each other, chase (each chased the other at different times) and a grand time was had by all. In the first couple of days there were a couple of barking spats when Kepler tried to eat out of the same food bowl as Curie but they were quickly resolved with no violence. Then the first Saturday I'd let them out to take care of business in the back yard and a fight broke out a few minutes later, I don't know why because I wasn't supervising them. When I pulled Kepler off Curie kept going after him, but when I pulled Curie off Kepler sat and immediately calmed down. Curie settled down after a few seconds. Kepler had some scratches on his face and Curie had some minor damage to one ear. The dogs were kept separate until the next morning when a friend could come over and hold a leash while I held the other, both dogs looked happy to see the other.

After that I split them up whenever I wasn't able to watch them, even when I was in the shower. Again they seemed to get along well, sharing toys, alternating beds, etc.

Wednesday a few days later I noticed Curie at her food bowl growling at Kepler. Kepler was standing a few feet away in his "casual interest" pose, not threatening but clearly Curie wasn't happy so I tried to intervene but I was too late, Curie lunged at Kepler and Kepler fought back and this time he wasn't backing down. To break up the fight I actually had to pick Curie up when they were near the bathroom door and push her inside then close the door. Again, both calmed down quickly once they were separated. This time Curie got the most damage with scratches on her face and neck and more ear damage. Kepler got a few minor scratches.

After that fight I began separating them during meal times, at first with one dog in a different room while the other stayed with me, but the dog in the different room often wouldn't eat so I started putting Kepler in his crate with his food while Curie stayed out (she doesn't have a crate yet and we're still working on crate training). Curie was fine with this, even when eating right next to Kepler's kennel. They would also get treats at the same time - closely supervised of course - and Curie was fine with it. It might help that Kepler tends to take his treats to another room to eat, something he did even before I got her. I did notice that Curie would freeze when Kepler started sniffing by her ear (which is still healing) but calling either of the dogs' names would be enough of a distraction that her tail would start wagging again.

A week went by and the household was in peace, but today I was doing yard work and Kepler and Curie were in the yard with me. They started to play, something I've seen them do several times and there haven't been any problems, but after a few minutes I looked over at them and noticed that Curie was playing more aggressively than usual and Kepler was no longer playing along, instead he was alternately standing still and trying to back away. She wasn't biting him, but she was rubbing the side of her face against the side of his face and neck and as I said Kepler clearly wasn't comfortable but couldn't get away. I tried to get there to pull her away but again I was too late and they started fighting. I don't know who threw the first "punch" but neither were backing down. To split up this fight I had to actually get between them and push them apart, once that was done they immediately calmed down. I kept a very light grip on their scruffs - it was almost more of a touch than a grip - but after about a minute of them just sitting there I slowly pulled away and went to the door. They walked almost side by side to the door and I let Curie, the one who got there first, inside then kept Kepler outside with me. Later, when I let the two meet again, Curie seemed happy to see him yet a little wary (but not defensive), and Kepler just looked happy to see her. Curie relaxed after a few minutes and went on as usual. I'm now keeping a very close eye on them when they're together.

The question: should I keep Curie? This is my first experience with two dogs, and I only have 8 months experience with a single dog. I figured the food aggression was manageable if not treatable, but now that I know she sometimes has issues playing too I don't know what to do. In the short term I can handle keeping the two completely separate but in the long term it would be too much - twice the walks, twice the social time, twice the play time, etc. If the situation is workable I'm willing to put in the work but if they're set up for a lifetime of animosity I don't want to force them to spend the next several years with that kind of stress.

I already set up an appointment with a behaviorist earlier this week but she can't come until Monday and I really don't want to spend $150 just to be told "Three fights is too many, you'll never be able to trust them together" so I figured I'd ask you much more knowledgeable folks here for suggestions.

Thanks in advance.