Gabriella, are you telling us you have Asperger's syndrome? Lack of understanding body language and not liking to make eye contact...
Many Aspies do better with online dating, being online in general gets rid of body language and eye contact and lets you connect with people by their words. Would that help you?
Otoh, if you have no desire to date or "fall in love" because your h desires you to do so, by all means make that perfectly clear to him. But if he feels the desire for a 2nd romantic partnership, and that idea makes you physically ill, you've got some work to do. Many here have done that work, as I am sure you have read.
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve. -- Shelley
There's no lying in polyamory!
I'm a 58 year old woman with 2 partners:
miss pixi, my live-in gf, 36 (together since Jan '09)
Ginger, bf, 61, married, lives nearby (together since Jan '12)