Yes, I think you are. What do you mean when you say you published the InfoPath form but it is checked out to you? When you publish your template, it does not go into the library itself. It goes into the hidden Forms folder (for back-end use only) and replaces the built-in template.xsn file that is there by default when you create your form library.
So, what file are you talking about that is checked out? It can't be a published template. Are you sure you didn't just upload your template straight to the library? Also, be aware that when you first upload a doc to a library and have never checked it in, no one else can see it. Your colleague will never see the doc if you've never checked it in. Once you check it in once, then there is an actual file there for others to see. After that, if you check it out, they will be able to open it read-only, and they will be looking at the most recently checked in version. However, none of this is applicable to a published template...