Actually, Mercury also rules tradesmen...so someone working within export/import can also be shown to have Mercury ruling the 10th.
But I think its someone else. I'd agree with most everything On the cusp is saying - this guy has lost interest in you, although he does still like you but not as before - Sun is still in Cancer so he still have some emotional connection to you, but his main significator has changed signs so his mind is on other things. I also think he puts himself first, because even though Sun is ruled by Cancer, Sun also exalts Jupiter (himself).
I do think marriage is there, Jupiter is significator of marriage in this chart, Moon will aspect it and is within orb of application. But first, you will go through issues with getting married to this guy and stress due to Moon square Venus and Jupiter Combusted. So this shows struggle and uncertainty.
As long as I remember, you've been going through many charts regarding different men that you were seeking to marry, at least for the past 2 years and I'd say this is the first chart that clearly shows marriage coming. But I think its an arranged marriage. Moon aspects show someone getting involved - perhaps a dating/matrimonial agency? Venus is a dual sign and also Moon, shows you looking at different men...looking at choices.
I'd suggest, give this current partner some time to think whether he wants to marry or not, if not perhaps you need to move forward.
all the best! Please update if you can