@Stanof53...
Glad that you are enjoying Malaysia and that you have found someone here that you can enjoy it with. Malaysia is a wonderful country that can provide a great quality of life to those willing to overlook the country's shortcomings and accept a few trade-offs (like anywhere else). BTW, I'm a Canadian, married to a Malay, and I've been living in Malaysia for the past 6-1/2 years.
One of the shortcomings is that rules and regulations here in Malaysia
1) are often not made publicly available
2) change constantly with no notice (and no updating of information on government websites either)
3) are all too often applied differently from state to state, between different offices of the same department, or between employees at the same office
4) are all too often applied differently depending on who you are ethnically and religiously
5) can be waived or enforced at the discretion of the officer you happen to be dealing with
This is why you will see differences between the official answers on the government website, and the answers of folks like Nemo and others -- including me -- in this forum whose experiences may differ quite dramatically from what various websites may lead you to expect.
The LTSVP application process is quick and fairly straight forward, especially at the main Immigration office in KL. A suggestion when applying for your LTSVP is to ask for the maximum duration possible on the application form. If you get less time than you asked for or need, then ask to speak to a senior officer and make your argument for a longer duration. Some things are open to negotiation, particularly if one goes in with a humble attitude instead of demanding rights that they don't have. If you get a shorter duration, ask for the reason behind it. You may be able to mitigate specific concerns that they may have. And although I've never experienced anyone at Immigration or anywhere else in government with their "hand out" to expedite things or bend the rules, DON'T EVER, EVER GO THAT ROUTE! The government has been clamping down on that kind of corruption and you can end up with a long prison stay as a result of greasing palms, regardless of whether the suggestion comes from you or the official that you're dealing with.
With respect to your question about long term residency in Malaysia, the Long Term Social Visit Pass (LTSVP) is the route to go for expat spouses of Malaysians. While it provides for an extended stay in Malaysia for up to 5 years at a time (subject to how much time you have left on your passport), it does NOT make you a Permanent Resident (PR). There is a separate process for applying to become a PR but, as the spouse of a Malaysian, you can generally only apply to become a PR after living here with your spouse for a minimum of 5 years. Even then, some expats will get their PR easily after 5 years, while others never get it no matter how long they've been living here, or how many times they apply. The LTSVP gives you just about all of the benefits that get as a PR and is far easier to get.
Regardless of whether you are living here in Malaysia under an LTSVP or as a PR, your status as a US citizen WILL NOT CHANGE, unless you renounce your US citizenship voluntarily.
One final word of advice is to seek the advice of a good US tax attorney who can advise you of the US income tax implications associated with living outside of the US, and those for your spouse of being married to an American. Many Malaysians married to Americans will be puzzled at being roped into the US income tax system despite not having been born in the US or not ever having lived there.
Hope this helps. Best wishes for a successful outcome for you and your partner.