Its never harmless at all pigzoom.
We learn about relationships from our parents, what did he learn from his mum and dad?.
Look at what you learnt about relationships and seek help to get all the crap unlearnt through counselling. You state you do not know what a good relationship is; I guess no-one ever bother to show you what one of those is like did they?. Its certainly not the relationship you are in now; he likely targeted you OP because your radar is well skewed.
The Freedom Programme for you may well be beneficial as would giving this man the boot as of now.
I would not believe his tears unlike the previous respondent; these can also be manipulative and designed to tug at your heartstrings. Look at his actions as well as his words OP; a man who tells you, "you need help, you do not get on with anyone" is someone who is projecting HIS own behaviour onto you.
Gaslighting is a form of psychological abuse “in which information is twisted or spun, selectively omitted to favor the abuser, or false information is presented with the intent of making victims doubt their own memory, perception, and sanity.”
Essentially, gaslighting is a tactic used to destabilize your understanding of reality, making you constantly doubt your own experiences.
Most of the time, this tactic is used to further uneven power balances with abusive partners, making you second guess yourself when you feel as if you are being abused or attacked.
Even if a relationship seems otherwise non-abusive, gaslighting is emotional and mental violence. This process in and of itself is toxic and unhealthy.
Do not even bother going to Relate with him. Joint counselling is never advisable when there is abuse of any sort within the relationship and make no mistake, this is abuse. NO decent counsellor would ever see the two of you together anyway.