Usual trademark of
MCP or people with high tendency to display possessiveness and
higher scope of control - In a simple paragraphy I am going to
explain below:
Love psychological effect; I must
know that my partner has nothing but my world in her and when that
happens, I am secured. Once I am secured, knowing other people of
the opposite gender doesn't matter because I won't run away - (this
is merely a thought). But she cannot do that because I am not her,
I cannot control her, but I can control myself.
Whether he can succeed in his control doesn't matter. MCP guys are
self-absorbed and cannot see reasoning beyond jealousy and
insecurity. 
You probably have two option on hand:
I) Talks things out. Usually, during this phrase, I won't emphasise
too much on this option because you will likely to trash things
without much physical evidence. Not saying you must purposely
source for that evidence to dis-credit him and release hell - but
paper cannot shield against fire for long - therefore I suggest
option II first.
II) Take time. Taking time isn't taking serious time to handle your
possible crisis. A good positive option is to dump in a little more
effort on your part, without the the suspicion and keep the
relationship going. Trust me, the more suspicious you are, the more
defensive he will get. The more natural and 'innocent' you are -
the more relax he is, the more mistakes he will commit unknowingly
(if something fishy is going on) and you would have see the whole
picture.
Cheers
