Need a Sci Fi sleuth/encyclopaedic mind

Hello, this is my very first post ever, anywhere. I've got a book series that I would like to finish but can't remember name of author or books! This has been bugging me for close to 15 years!

Basic premise-soldier and semi-sentient space/battle suit come to terms with each other (space suit previously trying to take over wearer)

All the details I remember:
A soldier wakes up on a recovery world. He has partial memory loss. Soldier is last survivor of knightly? order killed by their suits. In a series of flashbacks the solder realizes the battle suits were parasitic in nature and took over their wearer with each successive use. He is now seeking answers on different planets. He uses the suit sparingly. Meets a girl on the run who has psychic powers. First 3 novels came in one volume. Need next volume but can't remember the title or author!

Thanks for any help you can provide!

I borrowed it from the public library thinking I would see the following books but never did. Kicking myself for not noting any info down.