Yes, Stardew has multiple save slots to where you can have as many different games running as you want/need. I think I have 10 or 11 in my most often used computer.
No I'm not indecisive, or at least I think I'm not. Maybe.
Not quite unlimited but rather limited by your drive capacity. My SMAPI zipped saves vary in size a bit but none is larger than 740kb. With over 200Gb in my laptop's SDD, that's room for more saves than I could ever keep track of.