I would give it some time. You said you don't want to push him into anything, so don't. If you sit back and look at it, a year and 4 months is not a long time to be together before marriage and that's what he may be thinking, especially after what his first wife did to him. My husband and I have both been married before but he was divorced for a little over 3 years when we got married and he wanted to get married the second my divorce was final and it was a bit overwhelming at first. We did end up marrying right after my divorce was final but it scared me that he pushed so hard. I have no regrets, though.
It sounds like he definitely wants to marry you, so let him ask you in his own time. Who knows why men act the way they do?
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In raising my children, I have lost my mind but found my soul.