I couldn't imagine having only one! LOL
I have a 9 year old calico and an 8 year old tabby, both females. The calico is sweet and motherly; the tabby is tempermental (crabby) and jealous.
Last October, we acquired a new cat -- another female just a few months old. Of course, our sweet calico cat just loves the new one . . . but NOT crabby tabby. After all these months, crabby tabby still has not accepted the new girl. We still have to put up with hissy fits, chasing, slapping . . . fur flying . . .
But, crabby tabby has always had behavioral problems and personality quirks. If you have a good-natured cat like my old calico, getting a new cat shouldn't be a problem.
I absolutely love my girls . . . but as far as having my heart totally captured by an animal . . . that would have been the young, homeless male cat that "wormed" his way into my home last summer. OMG . . . I fell so in love with him! He was killed on the highway and I cried so hard . . . so what could I do? I adopted his homeless sister and found a home for another one of his sisters . . . (I'm still heartbroken!)
If you can give a home to another one, I sure hope you do . . . there are so many in need of good homes!