Debating on getting a second cat

Hello! My cat’s name is Lemon. He is 2 years old and I have had him since he was 12 weeks. He is my first ever cat and is the sweetest cat. He has never bit, scratched or done anything naughty. I adopted him from a humane society in my college town. He lived with me, my roommates and my roommates two cats. He got along SO well with their cats and played very hard with them. After I graduated college, I lived with my boyfriend’s family for 2 months. Lemon came with me and he had to live with my boyfriend’s family cat. The family cat wasn’t the friendliest and they didn’t play or snuggle together at all (which was based on the family cat, Lemon tried) but they tolerated each other fine.

After those two months, my boyfriend and I got our own place and we + Lemon moved in together. It’s been 4 months now since the move. Lemon loves me and my boyfriend - loves to meow at us, get pets from us, and just be in our presence. However, he also spends a lot of time sleeping under our bed.

With all this being said, I would really like to get another cat. My boyfriend and I have discussed it a lot and have had a hard time coming to a conclusion. My boyfriend is worried that because Lemon is so social with us, getting another cat could push him away from us and cause him to stay under the bed all the time. He doesn’t want Lemon to feel like we are replacing him (neither do I). On the other hand, I know how happy Lemon was with my roommate’s cats and how often/hard he played with them. Since he’s been alone, he hardly plays and spends most of the day sleeping (I know cats sleep a lot but some play is important). I’ve bought so many toys but he’s just not as interested as playing with another cat.

My boyfriend and I both have concerns about getting another cat and it not being a good fit for Lemon. We would have a very hard time adopting a cat and giving it up later on. However, we also don’t want to bring in another cat and have either cat be uncomfortable / not happy. All this being said I’m looking for some advice on whether we should adopt another cat.

Do you think Lemon would probably benefit from having someone to play with / be around since his whole life (up until 4 months ago) he has been surrounded by other cats?

Does he seem to be depressed/missing out on essential play time?

If we are to get another cat, should we get a kitten so we can try to train him to get along or should we get a cat closer to Lemon’s age so I can ask the shelter if the cat does well with other cats?

If I do get another cat, how can I best introduce them to each other so they get along?

Thank you so much! I appreciate any advice. I love Lemon so much and want to give him the best life. I don’t want to get another cat if I feel it isn’t a good idea. However, if it would benefit him I would love to give another cat a home!