I think as an adolescent youngster, Jasper would very much enjoy a feline companion to play with and keep him company while you are at work. However, I would hate to see you adopt another feline who you don't want, will feel jealous of, and may very well end up resenting. That could only result in a miserable life for the second cat. So, if you aren't prepared to offer another cat the same love you feel for Jasper, don't adopt one.

Laurie

I volunteer with a Siamese cat rescue group, have been owned by many Siamese cats over the years, and have interacted with hundred and hundreds of cats. Based on my personal experience and observations, I suggest you wait before deciding if Jasper needs a playmate. This is because:

1) The vast majority of cats really prefer to be alone. Cats are not group-focused like dogs are. They are independent and individual. So, for most cats, they are absolutely the happiest when they have the run of your house, with 100% access to your attention and love, with no competition.

2) Jasper, as you correctly deduced, is still afraid and traumatized by his shelter experience. He hasn't yet developed the confidence that you are now his forever "meowm" and that you will always be there for him, and that his home is permanently with you. Both Jasper and you need several months for him to relax, learn that he is safe and in his "forever" home. I've observed it can take as long as 6 months for a cat to develop this level of confidence and security. And one of my personal rescued cats required nearly 4 years before she really believed she was safe and at home.

3) Jasper needs time to settle into his new environment and make it his own.

My prediction is that Jasper will be very happy sharing your life as an "only" cat.

It's interesting that you didn't take your roommates cat with you because:

"Well, his drug problem (and refusal to admit he has one) ended our friendship, so needless to say I didn't take his cat."

The conclusion on whether to take the cat should not have been affected by your friendship with the current owner. In fact, many would have taken the cat to protect it. If you really wanted a second cat, the roommate's cat would have been the logical choice.

Since you've only had Jasper for a month, I'd recommend waiting for a year before you add another cat. This will give you time to understand if you want to have cats in your life long term. The shelters are full of cats returned by people with lifestyle changes.

Your love will be enough for Jasper, that and toys.

I did this with my last cat....before she was eaten by a coyote.
She was a female, about four years old. I adopted a male kitten from our shelter and I told them up front what I was
doing, seeing if my cat really wanted a friend. I put
a screen up at the doorway of a room and let the cats
interact through that over a period of about four days.
My cat never stopped hissing at the little kitten so I brought
the kitten back. Of course, the shelter kept the adoption fee.
But now, with my new cat, a younger cat, I am wondering if she is also bored, whether I am too big for her to play with. So I am thinking of doing the same thing. She doesn't seem quite happy enough and I feel as though I am her captor and have a responsibility to make her happy. It is the right thing to do. So at least try.