Cruise for 10th anniversary

Hi!

Next year my husband and I will celebrate 10 years. We’ve had a rough few years with me beating cancer and him being in school. We’d really like to just relax, have it be romantic, and not really a party vibe. We plan to do the spa, excursions, and eat a lot of good food. But not super older crowd either, I am 35 and he is 39! I can’t seem to find the best cruise line for us. Our budget is about $7,000. Any tips would be so appreciated! Thank you!