I've been in a similar situation and was off my bike for a few weeks at the beginning of the season last year due to tendonitis caused from improper fit. I thought it was my saddle, but turns out it was how the bike fit and where the saddle was positioned on my bike. That being said - have you been measured for a bike saddle? I know Specialized does this and you can go on their website and find which stores offer this service. If you are riding the correct size saddle, I'd look into bike fit next. Could be your saddle may be a little too forward or aft, nose tipped up or down, or seatpost too high or too low. It's amazing how small adjustments in these areas can translate to saddle pain.
I'm assuming you wear padded shorts? Sometimes having I'll-fitting shorts can cause discomfort. Friction can be a problem, too. I can't say enough good things about chamois butter.
And when all else fails, sometimes it's a matter of trial and error. Some shops have demo saddles available so you can try before you buy. I've personally found that my favorite saddle is the Specialized Ariel - but I tried a ton of other saddles first. Good luck and don't give up.
The Ruby Expert looks pretty minimalist, or what I would call uncomfortable! Petey makes good points about other possible contributors, though. I second the Specialized Ariel endorsement. Saddles are personal, but I think some have a lot more fans than others.
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