OP, you have to be 100% behind an abortion in order to never regret it.
I had one, years ago. Pregnancy was an accident, I never wanted a child (still don't, still childless), and I was never forced in to it. It was entirely my decision.
What he wants right now does not matter. You are talking about your physical and mental health: Pregnancy is a physical condition, it's just you whose body will change, who has to deal with potential symptoms such as morning sickness, tiredness, constant toilet visits, not to mention childbirth itself. An abortion would, besides it affecting you physically (you'll have severe cramps for a day or two after), potentially have a major impact on you mentally. It can send you in to depression if you feel it's the wrong decision for you and go through with it for someone else instead of you.
For both of these there is only one consideration, which is your wellbeing.
His comment about the 'trust' being gone is shockingly selfish given that he will never experience any of the above. HE CANNOT! I would argue he is not the right man for you if he puts his wants above your wellbeing.
You've had some great advice upthread but thought I'd add my side. Having gone through it I am absolutely certain that you'd need to be as convinced as I was about it. If you aren't, then you absolutely shouldn't.